結果

問題 No.2706 One Nafmo
ユーザー drken1215drken1215
提出日時 2024-03-31 14:01:21
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 2 ms / 2,000 ms
コード長 33,123 bytes
コンパイル時間 2,090 ms
コンパイル使用メモリ 210,544 KB
実行使用メモリ 6,820 KB
最終ジャッジ日時 2024-09-30 18:48:11
合計ジャッジ時間 2,704 ms
ジャッジサーバーID
(参考情報)
judge4 / judge1
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
6,820 KB
testcase_01 AC 1 ms
6,820 KB
testcase_02 AC 1 ms
6,820 KB
testcase_03 AC 1 ms
6,820 KB
testcase_04 AC 2 ms
6,816 KB
testcase_05 AC 1 ms
6,816 KB
testcase_06 AC 2 ms
6,820 KB
testcase_07 AC 1 ms
6,820 KB
testcase_08 AC 1 ms
6,816 KB
testcase_09 AC 1 ms
6,820 KB
testcase_10 AC 1 ms
6,820 KB
testcase_11 AC 1 ms
6,816 KB
testcase_12 AC 1 ms
6,816 KB
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ソースコード

diff #

#include <bits/stdc++.h>
using namespace std;

using pint = pair<int, int>;
using pll = pair<long long, long long>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

// 4-neighbor (or 8-neighbor)
const vector<int> dx = {1, 0, -1, 0, 1, -1, 1, -1};
const vector<int> dy = {0, 1, 0, -1, 1, 1, -1, -1};


/*///////////////////////////////////////////////////////*/
// debug
/*///////////////////////////////////////////////////////*/

#define DEBUG 1
#define COUT(x) if (DEBUG) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, deque<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ for (auto it : P) { s << "<" << it << "> "; } return s; }
template<class T> ostream& operator << (ostream &s, multiset<T> P)
{ for (auto it : P) { s << "<" << it << "> "; } return s; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ for (auto it : P) { s << "<" << it.first << "->" << it.second << "> "; } return s; }


/*///////////////////////////////////////////////////////*/
// QCFium 法
/*///////////////////////////////////////////////////////*/

#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")


/*/////////////////////////////*/
// modint, FPS
/*/////////////////////////////*/

// modint
template<int MOD> struct Fp {
    // inner value
    long long val;
    
    // constructor
    constexpr Fp() : val(0) { }
    constexpr Fp(long long v) : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr long long get() const { return val; }
    constexpr int get_mod() const { return MOD; }
    
    // arithmetic operators
    constexpr Fp operator + () const { return Fp(*this); }
    constexpr Fp operator - () const { return Fp(0) - Fp(*this); }
    constexpr Fp operator + (const Fp &r) const { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp &r) const { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp &r) const { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp &r) const { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp &r) {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp &r) {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp &r) {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp &r) {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b, swap(a, b);
            u -= t * v, swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp pow(long long n) const {
        Fp res(1), mul(*this);
        while (n > 0) {
            if (n & 1) res *= mul;
            mul *= mul;
            n >>= 1;
        }
        return res;
    }
    constexpr Fp inv() const {
        Fp res(1), div(*this);
        return res / div;
    }

    // other operators
    constexpr bool operator == (const Fp &r) const {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp &r) const {
        return this->val != r.val;
    }
    constexpr Fp& operator ++ () {
        ++val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -- () {
        if (val == 0) val += MOD;
        --val;
        return *this;
    }
    constexpr Fp operator ++ (int) const {
        Fp res = *this;
        ++*this;
        return res;
    }
    constexpr Fp operator -- (int) const {
        Fp res = *this;
        --*this;
        return res;
    }
    friend constexpr istream& operator >> (istream &is, Fp<MOD> &x) {
        is >> x.val;
        x.val %= MOD;
        if (x.val < 0) x.val += MOD;
        return is;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<MOD> &x) {
        return os << x.val;
    }
    friend constexpr Fp<MOD> pow(const Fp<MOD> &r, long long n) {
        return r.pow(n);
    }
    friend constexpr Fp<MOD> inv(const Fp<MOD> &r) {
        return r.inv();
    }
};

// Binomial coefficient
template<class mint> struct BiCoef {
    vector<mint> fact_, inv_, finv_;
    constexpr BiCoef() {}
    constexpr BiCoef(int n) : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
        init(n);
    }
    constexpr void init(int n) {
        fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
        int MOD = fact_[0].get_mod();
        for(int i = 2; i < n; i++){
            fact_[i] = fact_[i-1] * i;
            inv_[i] = -inv_[MOD%i] * (MOD/i);
            finv_[i] = finv_[i-1] * inv_[i];
        }
    }
    constexpr mint com(int n, int k) const {
        if (n < k || n < 0 || k < 0) return 0;
        return fact_[n] * finv_[k] * finv_[n-k];
    }
    constexpr mint fact(int n) const {
        if (n < 0) return 0;
        return fact_[n];
    }
    constexpr mint inv(int n) const {
        if (n < 0) return 0;
        return inv_[n];
    }
    constexpr mint finv(int n) const {
        if (n < 0) return 0;
        return finv_[n];
    }
};

namespace NTT {
    long long modpow(long long a, long long n, int mod) {
        long long res = 1;
        while (n > 0) {
            if (n & 1) res = res * a % mod;
            a = a * a % mod;
            n >>= 1;
        }
        return res;
    }

    long long modinv(long long a, int mod) {
        long long b = mod, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b, swap(a, b);
            u -= t * v, swap(u, v);
        }
        u %= mod;
        if (u < 0) u += mod;
        return u;
    }

    int calc_primitive_root(int mod) {
        if (mod == 2) return 1;
        if (mod == 167772161) return 3;
        if (mod == 469762049) return 3;
        if (mod == 754974721) return 11;
        if (mod == 998244353) return 3;
        int divs[20] = {};
        divs[0] = 2;
        int cnt = 1;
        long long x = (mod - 1) / 2;
        while (x % 2 == 0) x /= 2;
        for (long long i = 3; i * i <= x; i += 2) {
            if (x % i == 0) {
                divs[cnt++] = i;
                while (x % i == 0) x /= i;
            }
        }
        if (x > 1) divs[cnt++] = x;
        for (int g = 2;; g++) {
            bool ok = true;
            for (int i = 0; i < cnt; i++) {
                if (modpow(g, (mod - 1) / divs[i], mod) == 1) {
                    ok = false;
                    break;
                }
            }
            if (ok) return g;
        }
    }

    int get_fft_size(int N, int M) {
        int size_a = 1, size_b = 1;
        while (size_a < N) size_a <<= 1;
        while (size_b < M) size_b <<= 1;
        return max(size_a, size_b) << 1;
    }

    // number-theoretic transform
    template<class mint> void trans(vector<mint> &v, bool inv = false) {
        if (v.empty()) return;
        int N = (int)v.size();
        int MOD = v[0].get_mod();
        int PR = calc_primitive_root(MOD);
        static bool first = true;
        static vector<long long> vbw(30), vibw(30);
        if (first) {
            first = false;
            for (int k = 0; k < 30; ++k) {
                vbw[k] = modpow(PR, (MOD - 1) >> (k + 1), MOD);
                vibw[k] = modinv(vbw[k], MOD);
            }
        }
        for (int i = 0, j = 1; j < N - 1; j++) {
            for (int k = N >> 1; k > (i ^= k); k >>= 1);
            if (i > j) swap(v[i], v[j]);
        }
        for (int k = 0, t = 2; t <= N; ++k, t <<= 1) {
            long long bw = vbw[k];
            if (inv) bw = vibw[k];
            for (int i = 0; i < N; i += t) {
                mint w = 1;
                for (int j = 0; j < t/2; ++j) {
                    int j1 = i + j, j2 = i + j + t/2;
                    mint c1 = v[j1], c2 = v[j2] * w;
                    v[j1] = c1 + c2;
                    v[j2] = c1 - c2;
                    w *= bw;
                }
            }
        }
        if (inv) {
            long long invN = modinv(N, MOD);
            for (int i = 0; i < N; ++i) v[i] = v[i] * invN;
        }
    }

    // for garner
    static constexpr int MOD0 = 754974721;
    static constexpr int MOD1 = 167772161;
    static constexpr int MOD2 = 469762049;
    using mint0 = Fp<MOD0>;
    using mint1 = Fp<MOD1>;
    using mint2 = Fp<MOD2>;
    static const mint1 imod0 = 95869806; // modinv(MOD0, MOD1);
    static const mint2 imod1 = 104391568; // modinv(MOD1, MOD2);
    static const mint2 imod01 = 187290749; // imod1 / MOD0;

    // small case (T = mint, long long)
    template<class T> vector<T> naive_mul(const vector<T> &A, const vector<T> &B) {
        if (A.empty() || B.empty()) return {};
        int N = (int)A.size(), M = (int)B.size();
        vector<T> res(N + M - 1);
        for (int i = 0; i < N; ++i)
            for (int j = 0; j < M; ++j)
                res[i + j] += A[i] * B[j];
        return res;
    }

    // mul by convolution
    template<class mint> vector<mint> mul(const vector<mint> &A, const vector<mint> &B) {
        if (A.empty() || B.empty()) return {};
        int N = (int)A.size(), M = (int)B.size();
        if (min(N, M) < 30) return naive_mul(A, B);
        int MOD = A[0].get_mod();
        int size_fft = get_fft_size(N, M);
        if (MOD == 998244353) {
            vector<mint> a(size_fft), b(size_fft), c(size_fft);
            for (int i = 0; i < N; ++i) a[i] = A[i];
            for (int i = 0; i < M; ++i) b[i] = B[i];
            trans(a), trans(b);
            vector<mint> res(size_fft);
            for (int i = 0; i < size_fft; ++i) res[i] = a[i] * b[i];
            trans(res, true);
            res.resize(N + M - 1);
            return res;
        }
        vector<mint0> a0(size_fft, 0), b0(size_fft, 0), c0(size_fft, 0);
        vector<mint1> a1(size_fft, 0), b1(size_fft, 0), c1(size_fft, 0);
        vector<mint2> a2(size_fft, 0), b2(size_fft, 0), c2(size_fft, 0);
        for (int i = 0; i < N; ++i)
            a0[i] = A[i].val, a1[i] = A[i].val, a2[i] = A[i].val;
        for (int i = 0; i < M; ++i)
            b0[i] = B[i].val, b1[i] = B[i].val, b2[i] = B[i].val;
        trans(a0), trans(a1), trans(a2), trans(b0), trans(b1), trans(b2);
        for (int i = 0; i < size_fft; ++i) {
            c0[i] = a0[i] * b0[i];
            c1[i] = a1[i] * b1[i];
            c2[i] = a2[i] * b2[i];
        }
        trans(c0, true), trans(c1, true), trans(c2, true);
        mint mod0 = MOD0, mod01 = mod0 * MOD1;
        vector<mint> res(N + M - 1);
        for (int i = 0; i < N + M - 1; ++i) {
            int y0 = c0[i].val;
            int y1 = (imod0 * (c1[i] - y0)).val;
            int y2 = (imod01 * (c2[i] - y0) - imod1 * y1).val;
            res[i] = mod01 * y2 + mod0 * y1 + y0;
        }
        return res;
    }
};

// Formal Power Series
template<typename mint> struct FPS : vector<mint> {
    using vector<mint>::vector;
 
    // constructor
    constexpr FPS(const vector<mint> &r) : vector<mint>(r) {}
 
    // core operator
    constexpr FPS pre(int siz) const {
        return FPS(begin(*this), begin(*this) + min((int)this->size(), siz));
    }
    constexpr FPS rev() const {
        FPS res = *this;
        reverse(begin(res), end(res));
        return res;
    }
    constexpr FPS& normalize() {
        while (!this->empty() && this->back() == 0) this->pop_back();
        return *this;
    }
 
    // basic operator
    constexpr FPS operator - () const noexcept {
        FPS res = (*this);
        for (int i = 0; i < (int)res.size(); ++i) res[i] = -res[i];
        return res;
    }
    constexpr FPS operator + (const mint &v) const { return FPS(*this) += v; }
    constexpr FPS operator + (const FPS &r) const { return FPS(*this) += r; }
    constexpr FPS operator - (const mint &v) const { return FPS(*this) -= v; }
    constexpr FPS operator - (const FPS &r) const { return FPS(*this) -= r; }
    constexpr FPS operator * (const mint &v) const { return FPS(*this) *= v; }
    constexpr FPS operator * (const FPS &r) const { return FPS(*this) *= r; }
    constexpr FPS operator / (const mint &v) const { return FPS(*this) /= v; }
    constexpr FPS operator / (const FPS &r) const { return FPS(*this) /= r; }
    constexpr FPS operator % (const FPS &r) const { return FPS(*this) %= r; }
    constexpr FPS operator << (int x) const { return FPS(*this) <<= x; }
    constexpr FPS operator >> (int x) const { return FPS(*this) >>= x; }
    constexpr FPS& operator += (const mint &v) {
        if (this->empty()) this->resize(1);
        (*this)[0] += v;
        return *this;
    }
    constexpr FPS& operator += (const FPS &r) {
        if (r.size() > this->size()) this->resize(r.size());
        for (int i = 0; i < (int)r.size(); ++i) (*this)[i] += r[i];
        return this->normalize();
    }
    constexpr FPS& operator -= (const mint &v) {
        if (this->empty()) this->resize(1);
        (*this)[0] -= v;
        return *this;
    }
    constexpr FPS& operator -= (const FPS &r) {
        if (r.size() > this->size()) this->resize(r.size());
        for (int i = 0; i < (int)r.size(); ++i) (*this)[i] -= r[i];
        return this->normalize();
    }
    constexpr FPS& operator *= (const mint &v) {
        for (int i = 0; i < (int)this->size(); ++i) (*this)[i] *= v;
        return *this;
    }
    constexpr FPS& operator *= (const FPS &r) {
        return *this = NTT::mul((*this), r);
    }
    constexpr FPS& operator /= (const mint &v) {
        assert(v != 0);
        mint iv = modinv(v);
        for (int i = 0; i < (int)this->size(); ++i) (*this)[i] *= iv;
        return *this;
    }
    
    // division, r must be normalized (r.back() must not be 0)
    constexpr FPS& operator /= (const FPS &r) {
        assert(!r.empty());
        assert(r.back() != 0);
        this->normalize();
        if (this->size() < r.size()) {
            this->clear();
            return *this;
        }
        int need = (int)this->size() - (int)r.size() + 1;
        *this = (rev().pre(need) * r.rev().inv(need)).pre(need).rev();
        return *this;
    }
    constexpr FPS& operator %= (const FPS &r) {
        assert(!r.empty());
        assert(r.back() != 0);
        this->normalize();
        FPS q = (*this) / r;
        return *this -= q * r;
    }
    constexpr FPS& operator <<= (int x) {
        FPS res(x, 0);
        res.insert(res.end(), begin(*this), end(*this));
        return *this = res;
    }
    constexpr FPS& operator >>= (int x) {
        FPS res;
        res.insert(res.end(), begin(*this) + x, end(*this));
        return *this = res;
    }
    constexpr mint eval(const mint &v) {
        mint res = 0;
        for (int i = (int)this->size()-1; i >= 0; --i) {
            res *= v;
            res += (*this)[i];
        }
        return res;
    }

    // advanced operation
    // df/dx
    constexpr FPS diff() const {
        int n = (int)this->size();
        FPS res(n-1);
        for (int i = 1; i < n; ++i) res[i-1] = (*this)[i] * i;
        return res;
    }
    
    // \int f dx
    constexpr FPS integral() const {
        int n = (int)this->size();
        FPS res(n+1, 0);
        for (int i = 0; i < n; ++i) res[i+1] = (*this)[i] / (i+1);
        return res;
    }
    
    // inv(f), f[0] must not be 0
    constexpr FPS inv(int deg) const {
        assert((*this)[0] != 0);
        if (deg < 0) deg = (int)this->size();
        FPS res({mint(1) / (*this)[0]});
        for (int i = 1; i < deg; i <<= 1) {
            res = (res + res - res * res * pre(i << 1)).pre(i << 1);
        }
        res.resize(deg);
        return res;
    }
    constexpr FPS inv() const {
        return inv((int)this->size());
    }
    
    // log(f) = \int f'/f dx, f[0] must be 1
    constexpr FPS log(int deg) const {
        assert((*this)[0] == 1);
        FPS res = (diff() * inv(deg)).integral();
        res.resize(deg);
        return res;
    }
    constexpr FPS log() const {
        return log((int)this->size());
    }
    
    // exp(f), f[0] must be 0
    constexpr FPS exp(int deg) const {
        assert((*this)[0] == 0);
        FPS res(1, 1);
        for (int i = 1; i < deg; i <<= 1) {
            res = res * (pre(i << 1) - res.log(i << 1) + 1).pre(i << 1);
        }
        res.resize(deg);
        return res;
    }
    constexpr FPS exp() const {
        return exp((int)this->size());
    }
    
    // pow(f) = exp(e * log f)
    constexpr FPS pow(long long e, int deg) const {
        if (e == 0) {
            FPS res(deg, 0);
            res[0] = 1;
            return res;
        }
        long long i = 0;
        while (i < (int)this->size() && (*this)[i] == 0) ++i;
        if (i == (int)this->size() || i > (deg - 1) / e) return FPS(deg, 0);
        mint k = (*this)[i];
        FPS res = ((((*this) >> i) / k).log(deg) * e).exp(deg) * mint(k).pow(e) << (e * i);
        res.resize(deg);
        return res;
    }
    constexpr FPS pow(long long e) const {
        return pow(e, (int)this->size());
    }
    
    // sqrt(f), f[0] must be 1
    constexpr FPS sqrt_base(int deg) const {
        assert((*this)[0] == 1);
        mint inv2 = mint(1) / 2;
        FPS res(1, 1);
        for (int i = 1; i < deg; i <<= 1) {
            res = (res + pre(i << 1) * res.inv(i << 1)).pre(i << 1);
            for (mint &x : res) x *= inv2;
        }
        res.resize(deg);
        return res;
    }
    constexpr FPS sqrt_base() const {
        return sqrt_base((int)this->size());
    }
    
    // friend operators
    friend constexpr FPS diff(const FPS &f) { return f.diff(); }
    friend constexpr FPS integral(const FPS &f) { return f.integral(); }
    friend constexpr FPS inv(const FPS &f, int deg) { return f.inv(deg); }
    friend constexpr FPS inv(const FPS &f) { return f.inv((int)f.size()); }
    friend constexpr FPS log(const FPS &f, int deg) { return f.log(deg); }
    friend constexpr FPS log(const FPS &f) { return f.log((int)f.size()); }
    friend constexpr FPS exp(const FPS &f, int deg) { return f.exp(deg); }
    friend constexpr FPS exp(const FPS &f) { return f.exp((int)f.size()); }
    friend constexpr FPS pow(const FPS &f, long long e, int deg) { return f.pow(e, deg); }
    friend constexpr FPS pow(const FPS &f, long long e) { return f.pow(e, (int)f.size()); }
    friend constexpr FPS sqrt_base(const FPS &f, int deg) { return f.sqrt_base(deg); }
    friend constexpr FPS sqrt_base(const FPS &f) { return f.sqrt_base((int)f.size()); }
};


/*/////////////////////////////*/
// Union-Find
/*/////////////////////////////*/

// Union-Find
struct UnionFind {
    // core member
    vector<int> par, nex;

    // constructor
    UnionFind() { }
    UnionFind(int N) : par(N, -1), nex(N) {
        init(N);
    }
    void init(int N) {
        par.assign(N, -1);
        nex.resize(N);
        for (int i = 0; i < N; ++i) nex[i] = i;
    }
    
    // core methods
    int root(int x) {
        if (par[x] < 0) return x;
        else return par[x] = root(par[x]);
    }
    
    bool same(int x, int y) {
        return root(x) == root(y);
    }
    
    bool merge(int x, int y) {
        x = root(x), y = root(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y); // merge technique
        par[x] += par[y];
        par[y] = x;
        swap(nex[x], nex[y]);
        return true;
    }
    
    int size(int x) {
        return -par[root(x)];
    }
    
    // get group
    vector<int> group(int x) {
        vector<int> res({x});
        while (nex[res.back()] != x) res.push_back(nex[res.back()]);
        return res;
    }
    vector<vector<int>> groups() {
        vector<vector<int>> member(par.size());
        for (int v = 0; v < (int)par.size(); ++v) {
            member[root(v)].push_back(v);
        }
        vector<vector<int>> res;
        for (int v = 0; v < (int)par.size(); ++v) {
            if (!member[v].empty()) res.push_back(member[v]);
        }
        return res;
    }
    
    // debug
    friend ostream& operator << (ostream &s, UnionFind uf) {
        const vector<vector<int>> &gs = uf.groups();
        for (const vector<int> &g : gs) {
            s << "group: ";
            for (int v : g) s << v << " ";
            s << endl;
        }
        return s;
    }
};


/*/////////////////////////////*/
// Segment Tree
/*/////////////////////////////*/

// Segment Tree
template<class Monoid> struct SegmentTree {
    using Func = function<Monoid(Monoid, Monoid)>;

    // core member
    int N;
    Func OP;
    Monoid IDENTITY;
    
    // inner data
    int log, offset;
    vector<Monoid> dat;

    // constructor
    SegmentTree() {}
    SegmentTree(int n, const Func &op, const Monoid &identity) {
        init(n, op, identity);
    }
    SegmentTree(const vector<Monoid> &v, const Func &op, const Monoid &identity) {
        init(v, op, identity);
    }
    void init(int n, const Func &op, const Monoid &identity) {
        N = n;
        OP = op;
        IDENTITY = identity;
        log = 0, offset = 1;
        while (offset < N) ++log, offset <<= 1;
        dat.assign(offset * 2, IDENTITY);
    }
    void init(const vector<Monoid> &v, const Func &op, const Monoid &identity) {
        init((int)v.size(), op, identity);
        build(v);
    }
    void pull(int k) {
        dat[k] = OP(dat[k * 2], dat[k * 2 + 1]);
    }
    void build(const vector<Monoid> &v) {
        assert(N == (int)v.size());
        for (int i = 0; i < N; ++i) dat[i + offset] = v[i];
        for (int k = offset - 1; k > 0; --k) pull(k);
    }
    int size() const {
        return N;
    }
    Monoid operator [] (int i) const {
        return dat[i + offset];
    }
    
    // update A[i], i is 0-indexed, O(log N)
    void set(int i, const Monoid &v) {
        assert(0 <= i && i < N);
        int k = i + offset;
        dat[k] = v;
        while (k >>= 1) pull(k);
    }
    
    // get [l, r), l and r are 0-indexed, O(log N)
    Monoid prod(int l, int r) {
        assert(0 <= l && l <= r && r <= N);
        Monoid val_left = IDENTITY, val_right = IDENTITY;
        l += offset, r += offset;
        for (; l < r; l >>= 1, r >>= 1) {
            if (l & 1) val_left = OP(val_left, dat[l++]);
            if (r & 1) val_right = OP(dat[--r], val_right);
        }
        return OP(val_left, val_right);
    }
    Monoid all_prod() {
        return dat[1];
    }
    
    // get max r that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int max_right(const function<bool(Monoid)> f, int l = 0) {
        if (l == N) return N;
        l += offset;
        Monoid sum = IDENTITY;
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(OP(sum, dat[l]))) {
                while (l < offset) {
                    l = l * 2;
                    if (f(OP(sum, dat[l]))) {
                        sum = OP(sum, dat[l]);
                        ++l;
                    }
                }
                return l - offset;
            }
            sum = OP(sum, dat[l]);
            ++l;
        } while ((l & -l) != l);  // stop if l = 2^e
        return N;
    }

    // get min l that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int min_left(const function<bool(Monoid)> f, int r = -1) {
        if (r == 0) return 0;
        if (r == -1) r = N;
        r += offset;
        Monoid sum = IDENTITY;
        do {
            --r;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(OP(dat[r], sum))) {
                while (r < offset) {
                    r = r * 2 + 1;
                    if (f(OP(dat[r], sum))) {
                        sum = OP(dat[r], sum);
                        --r;
                    }
                }
                return r + 1 - offset;
            }
            sum = OP(dat[r], sum);
        } while ((r & -r) != r);
        return 0;
    }
    
    // debug
    friend ostream& operator << (ostream &s, const SegmentTree &seg) {
        for (int i = 0; i < (int)seg.size(); ++i) {
            s << seg[i];
            if (i != (int)seg.size() - 1) s << " ";
        }
        return s;
    }
};

// Lazy Segment Tree
template<class Monoid, class Action> struct LazySegmentTree {
    // various function types
    using FuncMonoid = function<Monoid(Monoid, Monoid)>;
    using FuncAction = function<Monoid(Action, Monoid)>;
    using FuncComposition = function<Action(Action, Action)>;

    // core member
    int N;
    FuncMonoid OP;
    FuncAction ACT;
    FuncComposition COMP;
    Monoid IDENTITY_MONOID;
    Action IDENTITY_ACTION;
    
    // inner data
    int log, offset;
    vector<Monoid> dat;
    vector<Action> lazy;
    
    // constructor
    LazySegmentTree() {}
    LazySegmentTree(int n, const FuncMonoid op, const FuncAction act, const FuncComposition comp,
                    const Monoid &identity_monoid, const Action &identity_action) {
        init(n, op, act, comp, identity_monoid, identity_action);
    }
    LazySegmentTree(const vector<Monoid> &v,
                    const FuncMonoid op, const FuncAction act, const FuncComposition comp,
                    const Monoid &identity_monoid, const Action &identity_action) {
        init(v, op, act, comp, identity_monoid, identity_action);
    }
    void init(int n, const FuncMonoid op, const FuncAction act, const FuncComposition comp,
              const Monoid &identity_monoid, const Action &identity_action) {
        N = n, OP = op, ACT = act, COMP = comp;
        IDENTITY_MONOID = identity_monoid, IDENTITY_ACTION = identity_action;
        log = 0, offset = 1;
        while (offset < N) ++log, offset <<= 1;
        dat.assign(offset * 2, IDENTITY_MONOID);
        lazy.assign(offset * 2, IDENTITY_ACTION);
    }
    void init(const vector<Monoid> &v,
              const FuncMonoid op, const FuncAction act, const FuncComposition comp,
              const Monoid &identity_monoid, const Action &identity_action) {
        init((int)v.size(), op, act, comp, identity_monoid, identity_action);
        build(v);
    }
    void build(const vector<Monoid> &v) {
        assert(N == (int)v.size());
        for (int i = 0; i < N; ++i) dat[i + offset] = v[i];
        for (int k = offset - 1; k > 0; --k) pull_dat(k);
    }
    int size() const {
        return N;
    }
    
    // basic functions for lazy segment tree
    void pull_dat(int k) {
        dat[k] = OP(dat[k * 2], dat[k * 2 + 1]);
    }
    void apply_lazy(int k, const Action &f) {
        dat[k] = ACT(f, dat[k]);
        if (k < offset) lazy[k] = COMP(f, lazy[k]);
    }
    void push_lazy(int k) {
        apply_lazy(k * 2, lazy[k]);
        apply_lazy(k * 2 + 1, lazy[k]);
        lazy[k] = IDENTITY_ACTION;
    }
    void pull_dat_deep(int k) {
        for (int h = 1; h <= log; ++h) pull_dat(k >> h);
    }
    void push_lazy_deep(int k) {
        for (int h = log; h >= 1; --h) push_lazy(k >> h);
    }
    
    // setter and getter, update A[i], i is 0-indexed, O(log N)
    void set(int i, const Monoid &v) {
        assert(0 <= i && i < N);
        int k = i + offset;
        push_lazy_deep(k);
        dat[k] = v;
        pull_dat_deep(k);
    }
    Monoid get(int i) {
        assert(0 <= i && i < N);
        int k = i + offset;
        push_lazy_deep(k);
        return dat[k];
    }
    Monoid operator [] (int i) {
        return get(i);
    }
    
    // apply f for index i
    void apply(int i, const Action &f) {
        assert(0 <= i && i < N);
        int k = i + offset;
        push_lazy_deep(k);
        dat[k] = ACT(f, dat[k]);
        pull_dat_deep(k);
    }
    // apply f for interval [l, r)
    void apply(int l, int r, const Action &f) {
        assert(0 <= l && l <= r && r <= N);
        if (l == r) return;
        l += offset, r += offset;
        for (int h = log; h >= 1; --h) {
            if (((l >> h) << h) != l) push_lazy(l >> h);
            if (((r >> h) << h) != r) push_lazy((r - 1) >> h);
        }
        int original_l = l, original_r = r;
        for (; l < r; l >>= 1, r >>= 1) {
            if (l & 1) apply_lazy(l++, f);
            if (r & 1) apply_lazy(--r, f);
        }
        l = original_l, r = original_r;
        for (int h = 1; h <= log; ++h) {
            if (((l >> h) << h) != l) pull_dat(l >> h);
            if (((r >> h) << h) != r) pull_dat((r - 1) >> h);
        }
    }
    
    // get prod of interval [l, r)
    Monoid prod(int l, int r) {
        assert(0 <= l && l <= r && r <= N);
        if (l == r) return IDENTITY_MONOID;
        l += offset, r += offset;
        for (int h = log; h >= 1; --h) {
            if (((l >> h) << h) != l) push_lazy(l >> h);
            if (((r >> h) << h) != r) push_lazy(r >> h);
        }
        Monoid val_left = IDENTITY_MONOID, val_right = IDENTITY_MONOID;
        for (; l < r; l >>= 1, r >>= 1) {
            if (l & 1) val_left = OP(val_left, dat[l++]);
            if (r & 1) val_right = OP(dat[--r], val_right);
        }
        return OP(val_left, val_right);
    }
    Monoid all_prod() {
        return dat[1];
    }
    
    // get max r that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int max_right(const function<bool(Monoid)> f, int l = 0) {
        if (l == N) return N;
        l += offset;
        push_lazy_deep(l);
        Monoid sum = IDENTITY_MONOID;
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(OP(sum, dat[l]))) {
                while (l < offset) {
                    push_lazy(l);
                    l = l * 2;
                    if (f(OP(sum, dat[l]))) {
                        sum = OP(sum, dat[l]);
                        ++l;
                    }
                }
                return l - offset;
            }
            sum = OP(sum, dat[l]);
            ++l;
        } while ((l & -l) != l);  // stop if l = 2^e
        return N;
    }

    // get min l that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int min_left(const function<bool(Monoid)> f, int r = -1) {
        if (r == 0) return 0;
        if (r == -1) r = N;
        r += offset;
        push_lazy_deep(r - 1);
        Monoid sum = IDENTITY_MONOID;
        do {
            --r;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(OP(dat[r], sum))) {
                while (r < offset) {
                    push_lazy(r);
                    r = r * 2 + 1;
                    if (f(OP(dat[r], sum))) {
                        sum = OP(dat[r], sum);
                        --r;
                    }
                }
                return r + 1 - offset;
            }
            sum = OP(dat[r], sum);
        } while ((r & -r) != r);
        return 0;
    }
    
    // debug stream
    friend ostream& operator << (ostream &s, LazySegmentTree seg) {
        for (int i = 0; i < (int)seg.size(); ++i) {
            s << seg[i];
            if (i != (int)seg.size() - 1) s << " ";
        }
        return s;
    }
    
    // dump
    void dump() {
        for (int i = 0; i <= log; ++i) {
            for (int j = (1 << i); j < (1 << (i + 1)); ++j) {
                cout << "{" << dat[j] << "," << lazy[j] << "} ";
            }
            cout << endl;
        }
    }
};



/*/////////////////////////////*/
// Solver
/*/////////////////////////////*/

/*
 const long long INF = 1LL<<60;
 int main() {
 int N, M;
 cin >> N >> M;
 vector<long long> A(N);
 for (int i = 0; i < N; ++i) cin >> A[i];
 
 using Edge = pair<int, long long>;
 using Graph = vector<vector<Edge>>;
 Graph G(N);
 for (int i = 0; i < M; ++i) {
 long long a, b, c;
 cin >> a >> b >> c;
 --a, --b;
 G[a].emplace_back(b, c);
 //G[b].emplace_back(a, c);
 }
 
 vector<long long> dp(N, -INF);
 vector<bool> negative(N, false);
 dp[0] = A[0];
 for (int iter = 0; iter < N; ++iter) {
 for (int v = 0; v < N; ++v) {
 if (dp[v] <= -INF/2) continue;
 for (auto e : G[v]) {
 chmax(dp[e.first], dp[v] - e.second + A[e.first]);
 }
 }
 }
 
 for (int iter = 0; iter <= N; ++iter) {
 for (int v = 0; v < N; ++v) {
 if (dp[v] <= -INF/2) continue;
 for (auto e : G[v]) {
 if (chmax(dp[e.first], dp[v] - e.second + A[e.first])) {
 negative[e.first] = true;
 }
 if (negative[v]) negative[e.first] = true;
 }
 }
 //COUT(dp);
 }
 if (!negative[N-1]) cout << dp[N-1] << endl;
 else cout << "inf" << endl;
 }
 */

int main() {
    int A, B, X;
    cin >> A >> B >> X;
    cout << (X + A - 1) / A * B << endl;
}
0