#pragma region Macros

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,fma,abm,mmx,avx,avx2")

#include <bits/extc++.h>
// #include <atcoder/all>
// using namespace atcoder;
using namespace std;
using namespace __gnu_pbds;

// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// using Bint = mp::cpp_int;
// using Bdouble = mp::number<mp::cpp_dec_float<256>>;

#define pb emplace_back
#define int ll
#define endl '\n'
#define sqrt __builtin_sqrtl

using ll = long long;
using ld = long double;
const ld PI = acosl(-1);
const int INF = 1 << 30;
const ll INFL = 1LL << 61;
const int MOD = 998244353;
// const int MOD = 1000000007;

const ld EPS = 1e-10;
const bool equals(ld a, ld b) { return fabs((a) - (b)) < EPS; }

const vector<int> dx = {0, 1, 0, -1, 1, 1, -1, -1}; // → ↓ ← ↑ ↘ ↙ ↖ ↗
const vector<int> dy = {1, 0, -1, 0, 1, -1, -1, 1};

struct Edge {
    int from, to;
    ll cost;
    Edge(int to, ll cost) : from(-1), to(to), cost(cost) {}
    Edge(int from, int to, ll cost) : from(from), to(to), cost(cost) {}
};

__attribute__((constructor))
void constructor() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(12);
}

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

int POW(int x, int n) {
    __int128_t ret = 1;
    // if (ret >= INFL) return INFL;
    if (n < 0) { cout << "error" << endl; return 0; }
    else if (x == 1 or n == 0) ret = 1;
    else if (x == -1 && n % 2 == 0) ret = 1; 
    else if (x == -1) ret = -1; 
    else if (n % 2 == 0) ret = POW(x * x, n / 2); // TODO:オーバーフロー対策
    else ret = x * POW(x, n - 1);

    if (ret > 8e18) ret = 0;
    return ret;
}
int floor(int x, int y) { return (x > 0 ? x / y : (x - y + 1) / y); }
int ceil(int x, int y) { return (x > 0 ? (x + y - 1) / y : x / y); }
ll per(int x, int y) {
    if (y == 0) {
        cout << "error" << endl;
        return INFL;
    }
    if (x >= 0 && y > 0) return x / y;
    if (x >= 0 && y < 0) return x / y - (x % y < 0);
    if (x < 0 && y < 0) return x / y + (x % y < 0);
    // if (x < 0 && y > 0) 
    return x / y - (x % y < 0);
}
ll mod(int x, int y) {
    if (y == 0) {
        cout << "error" << endl;
        return INFL;
    }
    if (x >= 0 && y > 0) return x % y;
    if (x >= 0 && y < 0) return x % y;
    if (x < 0 && y < 0) {
        __int128_t ret = x % y;
        ret += (__int128_t)abs(y) * INFL;
        ret %= abs(y);
        return ret;
    }
    // if (x < 0 && y > 0) {
        __int128_t ret = x % y;
        ret += (__int128_t)abs(y) * INFL;
        ret %= abs(y);
        return ret;
    // }
}
int modf(ld x) {
    if (equals(x, 0)) return 0;
	else if (x < 0) return ceill(x);
	else return floorl(x);
}

template <class T> bool chmax(T &a, const T& b) {
    if (a < b) { a = b; return true; }
    return false;
}
template <class T> bool chmin(T &a, const T& b) {
    if (a > b) { a = b; return true; }
    return false;
}

int countl_zero(int N) { return __builtin_clzll(N); }
int countl_one(int N) {
    int ret = 0; while (N % 2) { N /= 2; ret++; }
    return ret;
}
int countr_zero(int N) { return __builtin_ctzll(N); }
int countr_one(int N) {
    int ret = 0, k = 63 - __builtin_clzll(N);
    while (k != -1 && (N & (1LL << k))) { k--; ret++; }
    return ret;
}
int popcount(int N) { return __builtin_popcountll(N); }
int unpopcount(int N) { return 64 - __builtin_clzll(N) - __builtin_popcountll(N); }

int top_bit(int N) { return 63 - __builtin_clzll(N);} // 2^kの位
int bot_bit(int N) { return __builtin_ctz(N);} // 2^kの位
int MSB(int N) { return 1 << (63 - __builtin_clzll(N)); } // mask
// LSBどこいった?

int bit_width(int N) { return 64 - __builtin_clzll(N); } // 桁数
int ceil_log2(int N) { return 63 - __builtin_clzll(N); }
int bit_floor(int N) { return 1 << (63 - __builtin_clzll(N)); }
int floor_log2(int N) { return 64 - __builtin_clzll(N-1); }
int bit_ceil(int N) { return 1 << (64 - __builtin_clzll(N-1)) - (N==1); }

class UnionFind {
public:
	UnionFind() = default;
    UnionFind(int N) : par(N), sz(N, 1) {
        iota(par.begin(), par.end(), 0);
    }

	int root(int x) {
		if (par[x] == x) return x;
		return (par[x] = root(par[x]));
	}

	bool unite(int x, int y) {
		int rx = root(x);
		int ry = root(y);

        if (rx == ry) return false;
		if (sz[rx] < sz[ry]) swap(rx, ry);

		sz[rx] += sz[ry];
		par[ry] = rx;

        return true;
	}

	bool issame(int x, int y) { return (root(x) == root(y)); }
	int size(int x) { return sz[root(x)]; }

    vector<vector<int>> groups(int N) {
        vector<vector<int>> G(N);
        for (int x = 0; x < N; x++) {
            G[root(x)].push_back(x);
        }
		G.erase(
            remove_if(G.begin(), G.end(),
                [&](const vector<int>& V) { return V.empty(); }),
                    G.end());
        return G;
    }
private:
	vector<int> par;
	vector<int> sz;
};

template<int mod> class Modint{
public:
    int val = 0;
    Modint(int x = 0) { while (x < 0) x += mod; val = x % mod; }
    Modint(const Modint &r) { val = r.val; }

    Modint operator -() { return Modint(-val); } // 単項
    Modint operator +(const Modint &r) { return Modint(*this) += r; }
    Modint operator +(const int &q) { Modint r(q); return Modint(*this) += r; }
    Modint operator -(const Modint &r) { return Modint(*this) -= r; }
    Modint operator -(const int &q) { Modint r(q); return Modint(*this) -= r; }
    Modint operator *(const Modint &r) { return Modint(*this) *= r; }
    Modint operator *(const int &q) { Modint r(q); return Modint(*this) *= r; }
    Modint operator /(const Modint &r) { return Modint(*this) /= r; }
    Modint operator /(const int &q) { Modint r(q); return Modint(*this) /= r; }
    
    Modint& operator ++() { val++; if (val >= mod) val -= mod; return *this; } // 前置
    Modint operator ++(signed) { ++*this; return *this; } // 後置
    Modint& operator --() { val--; if (val < 0) val += mod; return *this; }
    Modint operator --(signed) { --*this; return *this; }
    Modint &operator +=(const Modint &r) { val += r.val; if (val >= mod) val -= mod; return *this; }
    Modint &operator +=(const int &q) { Modint r(q); val += r.val; if (val >= mod) val -= mod; return *this; }
    Modint &operator -=(const Modint &r) { if (val < r.val) val += mod; val -= r.val; return *this; }
    Modint &operator -=(const int &q) { Modint r(q);  if (val < r.val) val += mod; val -= r.val; return *this; }
    Modint &operator *=(const Modint &r) { val = val * r.val % mod; return *this; }
    Modint &operator *=(const int &q) { Modint r(q); val = val * r.val % mod; return *this; }
    Modint &operator /=(const Modint &r) {
        int a = r.val, b = mod, u = 1, v = 0;
        while (b) {int 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;
    }
    Modint &operator /=(const int &q) {
        Modint r(q); int a = r.val, b = mod, u = 1, v = 0;
        while (b) {int 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;
    }

    bool operator ==(const Modint& r) { return this -> val == r.val; }
    bool operator <(const Modint& r) { return this -> val < r.val; }
    bool operator >(const Modint& r) { return this -> val > r.val; }
    bool operator !=(const Modint& r) { return this -> val != r.val; }
};

using mint = Modint<MOD>;
// using Mint = modint998244353;

istream &operator >>(istream &is, mint& x) {
    int t; is >> t;
    x = t;
    return (is);
}
ostream &operator <<(ostream &os, const mint& x) {
    return os << x.val;
}
mint modpow(const mint &x, int n) {
    // TODO: n <= -1
    if (n == 0) return 1;
    mint t = modpow(x, n / 2);
    t = t * t;
    if (n & 1) t = t * x;
    return t;
}

int modpow(__int128_t x, int n, int mod) {
    // TODO: n <= -1
    __int128_t ret = 1;
    while (n > 0) {
        if (n % 2 == 1) ret = ret * x % mod;
        x = x * x % mod;
        n /= 2;
    }
    return ret;
}

int modinv(__int128_t x, int mod) {
    if (x == 1) return 1;
    return mod - modinv(mod % x, mod) * (mod / x) % mod;
}

istream &operator >>(istream &is, __int128_t& x) {
    string S; is >> S;
    __int128_t ret = 0;
    int f = 1;
    if (S[0] == '-') f = -1; 
    for (int i = 0; i < S.length(); i++)
        if ('0' <= S[i] && S[i] <= '9')
            ret = ret * 10 + S[i] - '0';
    x = ret * f;
    return (is);
}
ostream &operator <<(ostream &os, __int128_t x) {
    ostream::sentry s(os);
    if (s) {
        __uint128_t tmp = x < 0 ? -x : x;
        char buffer[128];
        char *d = end(buffer);

        do {
            --d;
            *d = "0123456789"[tmp % 10];
            tmp /= 10;
        } while (tmp != 0);

        if (x < 0) {
            --d;
            *d = '-';
        }
        int len = end(buffer) - d;

        if (os.rdbuf()->sputn(d, len) != len) {
            os.setstate(ios_base::badbit);
        }
    }
    return os;
}

__int128_t stoll(string &S) {
    __int128_t ret = 0;
    int f = 1;
    if (S[0] == '-') f = -1; 
    for (int i = 0; i < S.length(); i++)
        if ('0' <= S[i] && S[i] <= '9')
            ret = ret * 10 + S[i] - '0';
    return ret * f;
}
__int128_t gcd(__int128_t a, __int128_t b) {
    return b ? gcd(b, a % b) : a;
}
__int128_t lcm(__int128_t a, __int128_t b) {
    return a / gcd(a, b) * b;
    // lcmが__int128_tに収まる必要あり
}

string to_string(__int128_t x) {
    string ret = "";
    if (x < 0) {
        ret += "-";
        x *= -1;
    }
    while (x) {
        ret += (char)('0' + x % 10);
        x /= 10;
    }
    reverse(ret.begin(), ret.end());
    return ret;
}
string to_string(char c) { // バグってる?
    string s = {c};
    return s;
}

vector<mint> _fac, _finv, _inv;
void COMinit(int N) {
    _fac.resize(N + 1);
    _finv.resize(N + 1);
    _inv.resize(N + 1);
    _fac[0] = _fac[1] = 1;
    _finv[0] = _finv[1] = 1;
    _inv[1] = 1;
    for (int i = 2; i <= N; i++) {
        _fac[i] = _fac[i-1] * mint(i);
        _inv[i] = -_inv[MOD % i] * mint(MOD / i);
        _finv[i] = _finv[i - 1] * _inv[i];
    }
}

mint FAC(int N) {
    if (N < 0) return 0;
    return _fac[N];
}
mint COM(int N, int K) {
    if (N < K) return 0;
    if (N < 0 or K < 0) return 0;
    return _fac[N] * _finv[K] * _finv[N - K];
}
mint PERM(int N, int K) {
    if (N < K) return 0;
    if (N < 0 or K < 0) return 0;
    return _fac[N] *  _finv[N - K];
}
mint NHK(int N, int K) {
    if (N == 0 && K == 0)  return 1;
    return COM(N + K - 1, K);
}

#pragma endregion

signed main() {
    int H, A;
    cin >> H >> A;
    int ans = 0;
    int cur = 1;
    while (H > 0) {
        H /= A;
        ans += cur;
        cur *= 2;
    }
    cout << ans << endl;
}