/** * date : 2023-07-31 08:33:02 * author : Nyaan */ #define NDEBUG using namespace std; // intrinstic #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // utility namespace Nyaan { using ll = long long; using i64 = long long; using u64 = unsigned long long; using i128 = __int128_t; using u128 = __uint128_t; template using V = vector; template using VV = vector>; using vi = vector; using vl = vector; using vd = V; using vs = V; using vvi = vector>; using vvl = vector>; template using minpq = priority_queue, greater>; template struct P : pair { template P(Args... args) : pair(args...) {} using pair::first; using pair::second; P &operator+=(const P &r) { first += r.first; second += r.second; return *this; } P &operator-=(const P &r) { first -= r.first; second -= r.second; return *this; } P &operator*=(const P &r) { first *= r.first; second *= r.second; return *this; } template P &operator*=(const S &r) { first *= r, second *= r; return *this; } P operator+(const P &r) const { return P(*this) += r; } P operator-(const P &r) const { return P(*this) -= r; } P operator*(const P &r) const { return P(*this) *= r; } template P operator*(const S &r) const { return P(*this) *= r; } P operator-() const { return P{-first, -second}; } }; using pl = P; using pi = P; using vp = V; constexpr int inf = 1001001001; constexpr long long infLL = 4004004004004004004LL; template int sz(const T &t) { return t.size(); } template inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; } template inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; } template inline T Max(const vector &v) { return *max_element(begin(v), end(v)); } template inline T Min(const vector &v) { return *min_element(begin(v), end(v)); } template inline long long Sum(const vector &v) { return accumulate(begin(v), end(v), 0LL); } template int lb(const vector &v, const T &a) { return lower_bound(begin(v), end(v), a) - begin(v); } template int ub(const vector &v, const T &a) { return upper_bound(begin(v), end(v), a) - begin(v); } constexpr long long TEN(int n) { long long ret = 1, x = 10; for (; n; x *= x, n >>= 1) ret *= (n & 1 ? x : 1); return ret; } template pair mkp(const T &t, const U &u) { return make_pair(t, u); } template vector mkrui(const vector &v, bool rev = false) { vector ret(v.size() + 1); if (rev) { for (int i = int(v.size()) - 1; i >= 0; i--) ret[i] = v[i] + ret[i + 1]; } else { for (int i = 0; i < int(v.size()); i++) ret[i + 1] = ret[i] + v[i]; } return ret; }; template vector mkuni(const vector &v) { vector ret(v); sort(ret.begin(), ret.end()); ret.erase(unique(ret.begin(), ret.end()), ret.end()); return ret; } template vector mkord(int N, F f) { vector ord(N); iota(begin(ord), end(ord), 0); sort(begin(ord), end(ord), f); return ord; } template vector mkinv(vector &v) { int max_val = *max_element(begin(v), end(v)); vector inv(max_val + 1, -1); for (int i = 0; i < (int)v.size(); i++) inv[v[i]] = i; return inv; } vector mkiota(int n) { vector ret(n); iota(begin(ret), end(ret), 0); return ret; } template T mkrev(const T &v) { T w{v}; reverse(begin(w), end(w)); return w; } template bool nxp(vector &v) { return next_permutation(begin(v), end(v)); } // 返り値の型は入力の T に依存 // i 要素目 : [0, a[i]) template vector> product(const vector &a) { vector> ret; vector v; auto dfs = [&](auto rc, int i) -> void { if (i == (int)a.size()) { ret.push_back(v); return; } for (int j = 0; j < a[i]; j++) v.push_back(j), rc(rc, i + 1), v.pop_back(); }; dfs(dfs, 0); return ret; } // F : function(void(T&)), mod を取る操作 // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I, const function &f) { T res = I; for (; n; f(a = a * a), n >>= 1) { if (n & 1) f(res = res * a); } return res; } // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I) { return Power(a, n, I, function{[](T &) -> void {}}); } } // namespace Nyaan // bit operation namespace Nyaan { __attribute__((target("popcnt"))) inline int popcnt(const u64 &a) { return _mm_popcnt_u64(a); } inline int lsb(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int ctz(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int msb(const u64 &a) { return a ? 63 - __builtin_clzll(a) : -1; } template inline int gbit(const T &a, int i) { return (a >> i) & 1; } template inline void sbit(T &a, int i, bool b) { if (gbit(a, i) != b) a ^= T(1) << i; } constexpr long long PW(int n) { return 1LL << n; } constexpr long long MSK(int n) { return (1LL << n) - 1; } } // namespace Nyaan // inout namespace Nyaan { template ostream &operator<<(ostream &os, const pair &p) { os << p.first << " " << p.second; return os; } template istream &operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } template ostream &operator<<(ostream &os, const vector &v) { int s = (int)v.size(); for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i]; return os; } template istream &operator>>(istream &is, vector &v) { for (auto &x : v) is >> x; return is; } istream &operator>>(istream &is, __int128_t &x) { string S; is >> S; x = 0; int flag = 0; for (auto &c : S) { if (c == '-') { flag = true; continue; } x *= 10; x += c - '0'; } if (flag) x = -x; return is; } istream &operator>>(istream &is, __uint128_t &x) { string S; is >> S; x = 0; for (auto &c : S) { x *= 10; x += c - '0'; } return is; } ostream &operator<<(ostream &os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } ostream &operator<<(ostream &os, __uint128_t x) { if (x == 0) return os << 0; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } void in() {} template void in(T &t, U &...u) { cin >> t; in(u...); } void out() { cout << "\n"; } template void out(const T &t, const U &...u) { cout << t; if (sizeof...(u)) cout << sep; out(u...); } struct IoSetupNya { IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7); } } iosetupnya; } // namespace Nyaan // debug #ifdef NyaanDebug #define trc(...) (void(0)) #else #define trc(...) (void(0)) #endif #ifdef NyaanLocal #define trc2(...) (void(0)) #else #define trc2(...) (void(0)) #endif // macro #define each(x, v) for (auto&& x : v) #define each2(x, y, v) for (auto&& [x, y] : v) #define all(v) (v).begin(), (v).end() #define rep(i, N) for (long long i = 0; i < (long long)(N); i++) #define repr(i, N) for (long long i = (long long)(N)-1; i >= 0; i--) #define rep1(i, N) for (long long i = 1; i <= (long long)(N); i++) #define repr1(i, N) for (long long i = (N); (long long)(i) > 0; i--) #define reg(i, a, b) for (long long i = (a); i < (b); i++) #define regr(i, a, b) for (long long i = (b)-1; i >= (a); i--) #define fi first #define se second #define ini(...) \ int __VA_ARGS__; \ in(__VA_ARGS__) #define inl(...) \ long long __VA_ARGS__; \ in(__VA_ARGS__) #define ins(...) \ string __VA_ARGS__; \ in(__VA_ARGS__) #define in2(s, t) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i]); \ } #define in3(s, t, u) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i]); \ } #define in4(s, t, u, v) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i], v[i]); \ } #define die(...) \ do { \ Nyaan::out(__VA_ARGS__); \ return; \ } while (0) namespace Nyaan { void solve(); } int main() { Nyaan::solve(); } // using namespace Nyaan; // x / y (x > 0, y > 0) を管理、デフォルトで 1 / 1 // 入力が互いに素でない場合は gcd を取って格納 // seq : (1, 1) から (x, y) へのパス。右の子が正/左の子が負 template struct SternBrocotTreeNode { using Node = SternBrocotTreeNode; Int lx, ly, x, y, rx, ry; vector seq; SternBrocotTreeNode() : lx(0), ly(1), x(1), y(1), rx(1), ry(0) {} SternBrocotTreeNode(Int X, Int Y) : SternBrocotTreeNode() { assert(1 <= X && 1 <= Y); Int g = gcd(X, Y); X /= g, Y /= g; while (min(X, Y) > 0) { if (X > Y) { int d = X / Y; X -= d * Y; go_right(d - (X == 0 ? 1 : 0)); } else { int d = Y / X; Y -= d * X; go_left(d - (Y == 0 ? 1 : 0)); } } } SternBrocotTreeNode(const pair &xy) : SternBrocotTreeNode(xy.first, xy.second) {} SternBrocotTreeNode(const vector &_seq) : SternBrocotTreeNode() { for (const Int &d : _seq) { assert(d != 0); if (d > 0) go_right(d); if (d < 0) go_left(d); } assert(seq == _seq); } // pair 型で分数を get pair get() const { return make_pair(x, y); } // 区間の下限 pair lower_bound() const { return make_pair(lx, ly); } // 区間の上限 pair upper_bound() const { return make_pair(rx, ry); } // 根からの深さ Int depth() const { Int res = 0; for (auto &s : seq) res += abs(s); return res; } // 左の子に d 進む void go_left(Int d = 1) { if (d <= 0) return; if (seq.empty() or seq.back() > 0) seq.push_back(0); seq.back() -= d; rx += lx * d, ry += ly * d; x = rx + lx, y = ry + ly; } // 右の子に d 進む void go_right(Int d = 1) { if (d <= 0) return; if (seq.empty() or seq.back() < 0) seq.push_back(0); seq.back() += d; lx += rx * d, ly += ry * d; x = rx + lx, y = ry + ly; } // 親の方向に d 進む // d 進めたら true, 進めなかったら false を返す bool go_parent(Int d = 1) { if (d <= 0) return true; while (d) { if (seq.empty()) return false; Int d2 = min(d, abs(seq.back())); if (seq.back() > 0) { x -= rx * d2, y -= ry * d2; lx = x - rx, ly = y - ry; seq.back() -= d2; } else { x -= lx * d2, y -= ly * d2; rx = x - lx, ry = y - ly; seq.back() += d2; } d -= d2; if (seq.back() == 0) seq.pop_back(); if (d2 == Int{0}) break; } return true; } // SBT 上の LCA static Node lca(const Node &lhs, const Node &rhs) { Node n; for (int i = 0; i < min(lhs.seq.size(), rhs.seq.size()); i++) { Int val1 = lhs.seq[i], val2 = rhs.seq[i]; if ((val1 < 0) != (val2 < 0)) break; if (val1 < 0) n.go_left(min(-val1, -val2)); if (val1 > 0) n.go_right(min(val1, val2)); if (val1 != val2) break; } return n; } friend ostream &operator<<(ostream &os, const Node &rhs) { os << "\n"; os << "L : ( " << rhs.lx << ", " << rhs.ly << " )\n"; os << "M : ( " << rhs.x << ", " << rhs.y << " )\n"; os << "R : ( " << rhs.rx << ", " << rhs.ry << " )\n"; os << "seq : " << rhs.seq << "\n"; return os; } friend bool operator<(const Node &lhs, const Node &rhs) { return lhs.x * rhs.y < rhs.x * lhs.y; } friend bool operator==(const Node &lhs, const Node &rhs) { return lhs.x == rhs.x and lhs.y == rhs.y; } }; // f(x) が true, かつ分子と分母が INF 以下である最小の既約分数 x を求める // f(0) = true の場合は 0 を, true になる分数が存在しない場合は 1/0 を返す template pair binary_search_on_stern_brocot_tree(function)> f, const I &INF) { // INF >= 1 assert(1 <= INF); SternBrocotTreeNode m; // INF 条件を超える or f(m) = return_value である auto over = [&](bool return_value) { return max(m.x, m.y) > INF or f(m.get()) == return_value; }; if (f(make_pair(0, 1))) return m.lower_bound(); int go_left = over(true); for (; true; go_left ^= 1) { if (go_left) { // f(M) = true -> (L, M] に答えがある // (f(L * b + M) = false) or (INF 超え) になる b の最小は? I a = 1; for (; true; a *= 2) { m.go_left(a); if (over(false)) { m.go_parent(a); break; } } for (a /= 2; a; a /= 2) { m.go_left(a); if (over(false)) m.go_parent(a); } m.go_left(1); if (max(m.get().first, m.get().second) > INF) return m.upper_bound(); } else { // f(M) = false -> (M, R] に答えがある // (f(M + R * b) = true) or (INF 超え) になる b の最小は? I a = 1; for (; true; a *= 2) { m.go_right(a); if (over(true)) { m.go_parent(a); break; } } for (a /= 2; a; a /= 2) { m.go_right(a); if (over(true)) m.go_parent(a); } m.go_right(1); if (max(m.get().first, m.get().second) > INF) return m.upper_bound(); } } } using namespace Nyaan; using SBT = SternBrocotTreeNode; #ifdef _MSC_VER #include #endif namespace atcoder { namespace internal { // @param m `1 <= m` // @return x mod m constexpr long long safe_mod(long long x, long long m) { x %= m; if (x < 0) x += m; return x; } // Fast modular multiplication by barrett reduction // Reference: https://en.wikipedia.org/wiki/Barrett_reduction // NOTE: reconsider after Ice Lake struct barrett { unsigned int _m; unsigned long long im; // @param m `1 <= m < 2^31` barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {} // @return m unsigned int umod() const { return _m; } // @param a `0 <= a < m` // @param b `0 <= b < m` // @return `a * b % m` unsigned int mul(unsigned int a, unsigned int b) const { // [1] m = 1 // a = b = im = 0, so okay // [2] m >= 2 // im = ceil(2^64 / m) // -> im * m = 2^64 + r (0 <= r < m) // let z = a*b = c*m + d (0 <= c, d < m) // a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im // c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2 // ((ab * im) >> 64) == c or c + 1 unsigned long long z = a; z *= b; #ifdef _MSC_VER unsigned long long x; _umul128(z, im, &x); #else unsigned long long x = (unsigned long long)(((unsigned __int128)(z)*im) >> 64); #endif unsigned int v = (unsigned int)(z - x * _m); if (_m <= v) v += _m; return v; } }; // @param n `0 <= n` // @param m `1 <= m` // @return `(x ** n) % m` constexpr long long pow_mod_constexpr(long long x, long long n, int m) { if (m == 1) return 0; unsigned int _m = (unsigned int)(m); unsigned long long r = 1; unsigned long long y = safe_mod(x, m); while (n) { if (n & 1) r = (r * y) % _m; y = (y * y) % _m; n >>= 1; } return r; } // Reference: // M. Forisek and J. Jancina, // Fast Primality Testing for Integers That Fit into a Machine Word // @param n `0 <= n` constexpr bool is_prime_constexpr(int n) { if (n <= 1) return false; if (n == 2 || n == 7 || n == 61) return true; if (n % 2 == 0) return false; long long d = n - 1; while (d % 2 == 0) d /= 2; constexpr long long bases[3] = {2, 7, 61}; for (long long a : bases) { long long t = d; long long y = pow_mod_constexpr(a, t, n); while (t != n - 1 && y != 1 && y != n - 1) { y = y * y % n; t <<= 1; } if (y != n - 1 && t % 2 == 0) { return false; } } return true; } template constexpr bool is_prime = is_prime_constexpr(n); // @param b `1 <= b` // @return pair(g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g constexpr std::pair inv_gcd(long long a, long long b) { a = safe_mod(a, b); if (a == 0) return {b, 0}; // Contracts: // [1] s - m0 * a = 0 (mod b) // [2] t - m1 * a = 0 (mod b) // [3] s * |m1| + t * |m0| <= b long long s = b, t = a; long long m0 = 0, m1 = 1; while (t) { long long u = s / t; s -= t * u; m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b // [3]: // (s - t * u) * |m1| + t * |m0 - m1 * u| // <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u) // = s * |m1| + t * |m0| <= b auto tmp = s; s = t; t = tmp; tmp = m0; m0 = m1; m1 = tmp; } // by [3]: |m0| <= b/g // by g != b: |m0| < b/g if (m0 < 0) m0 += b / s; return {s, m0}; } // Compile time primitive root // @param m must be prime // @return primitive root (and minimum in now) constexpr int primitive_root_constexpr(int m) { if (m == 2) return 1; if (m == 167772161) return 3; if (m == 469762049) return 3; if (m == 754974721) return 11; if (m == 998244353) return 3; int divs[20] = {}; divs[0] = 2; int cnt = 1; int x = (m - 1) / 2; while (x % 2 == 0) x /= 2; for (int i = 3; (long long)(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 (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) { ok = false; break; } } if (ok) return g; } } template constexpr int primitive_root = primitive_root_constexpr(m); } // namespace internal } // namespace atcoder namespace atcoder { long long pow_mod(long long x, long long n, int m) { assert(0 <= n && 1 <= m); if (m == 1) return 0; internal::barrett bt((unsigned int)(m)); unsigned int r = 1, y = (unsigned int)(internal::safe_mod(x, m)); while (n) { if (n & 1) r = bt.mul(r, y); y = bt.mul(y, y); n >>= 1; } return r; } long long inv_mod(long long x, long long m) { assert(1 <= m); auto z = internal::inv_gcd(x, m); assert(z.first == 1); return z.second; } // (rem, mod) std::pair crt(const std::vector& r, const std::vector& m) { assert(r.size() == m.size()); int n = int(r.size()); // Contracts: 0 <= r0 < m0 long long r0 = 0, m0 = 1; for (int i = 0; i < n; i++) { assert(1 <= m[i]); long long r1 = internal::safe_mod(r[i], m[i]), m1 = m[i]; if (m0 < m1) { std::swap(r0, r1); std::swap(m0, m1); } if (m0 % m1 == 0) { if (r0 % m1 != r1) return {0, 0}; continue; } // assume: m0 > m1, lcm(m0, m1) >= 2 * max(m0, m1) // (r0, m0), (r1, m1) -> (r2, m2 = lcm(m0, m1)); // r2 % m0 = r0 // r2 % m1 = r1 // -> (r0 + x*m0) % m1 = r1 // -> x*u0*g % (u1*g) = (r1 - r0) (u0*g = m0, u1*g = m1) // -> x = (r1 - r0) / g * inv(u0) (mod u1) // im = inv(u0) (mod u1) (0 <= im < u1) long long g, im; std::tie(g, im) = internal::inv_gcd(m0, m1); long long u1 = (m1 / g); // |r1 - r0| < (m0 + m1) <= lcm(m0, m1) if ((r1 - r0) % g) return {0, 0}; // u1 * u1 <= m1 * m1 / g / g <= m0 * m1 / g = lcm(m0, m1) long long x = (r1 - r0) / g % u1 * im % u1; // |r0| + |m0 * x| // < m0 + m0 * (u1 - 1) // = m0 + m0 * m1 / g - m0 // = lcm(m0, m1) r0 += x * m0; m0 *= u1; // -> lcm(m0, m1) if (r0 < 0) r0 += m0; } return {r0, m0}; } long long floor_sum(long long n, long long m, long long a, long long b) { long long ans = 0; if (a < 0) { unsigned long long a2 = internal::safe_mod(a, m); ans -= 1ULL * n * (n - 1) / 2 * ((a2 - a) / m); a = a2; } if (b < 0) { unsigned long long b2 = internal::safe_mod(b, m); ans -= 1ULL * n * ((b2 - b) / m); b = b2; } if (a >= m) { ans += (n - 1) * n * (a / m) / 2; a %= m; } if (b >= m) { ans += n * (b / m); b %= m; } long long y_max = (a * n + b) / m, x_max = (y_max * m - b); if (y_max == 0) return ans; ans += (n - (x_max + a - 1) / a) * y_max; ans += floor_sum(y_max, a, m, (a - x_max % a) % a); return ans; } } // namespace atcoder // using namespace std; using namespace std; namespace internal { template using is_broadly_integral = typename conditional_t || is_same_v || is_same_v, true_type, false_type>::type; template using is_broadly_signed = typename conditional_t || is_same_v, true_type, false_type>::type; template using is_broadly_unsigned = typename conditional_t || is_same_v, true_type, false_type>::type; #define ENABLE_VALUE(x) \ template \ constexpr bool x##_v = x::value; ENABLE_VALUE(is_broadly_integral); ENABLE_VALUE(is_broadly_signed); ENABLE_VALUE(is_broadly_unsigned); #undef ENABLE_VALUE #define ENABLE_HAS_TYPE(var) \ template \ struct has_##var : std::false_type {}; \ template \ struct has_##var> : std::true_type {}; \ template \ constexpr auto has_##var##_v = has_##var::value; } // namespace internal using namespace std; namespace BinaryGCDImpl { using u64 = unsigned long long; using i8 = char; u64 binary_gcd(u64 a, u64 b) { if (a == 0 || b == 0) return a + b; i8 n = __builtin_ctzll(a); i8 m = __builtin_ctzll(b); a >>= n; b >>= m; n = min(n, m); while (a != b) { u64 d = a - b; i8 s = __builtin_ctzll(d); bool f = a > b; b = f ? b : a; a = (f ? d : -d) >> s; } return a << n; } using u128 = __uint128_t; // a > 0 int ctz128(u128 a) { u64 lo = a & u64(-1); return lo ? __builtin_ctzll(lo) : 64 + __builtin_ctzll(a >> 64); } u128 binary_gcd128(u128 a, u128 b) { if (a == 0 || b == 0) return a + b; i8 n = ctz128(a); i8 m = ctz128(b); a >>= n; b >>= m; n = min(n, m); while (a != b) { u128 d = a - b; i8 s = ctz128(d); bool f = a > b; b = f ? b : a; a = (f ? d : -d) >> s; } return a << n; } } // namespace BinaryGCDImpl long long binary_gcd(long long a, long long b) { return BinaryGCDImpl::binary_gcd(abs(a), abs(b)); } __int128_t binary_gcd128(__int128_t a, __int128_t b) { if (a < 0) a = -a; if (b < 0) b = -b; return BinaryGCDImpl::binary_gcd128(a, b); } /** * @brief binary GCD */ // T : 値, U : 比較用 template struct RationalBase { using R = RationalBase; using Key = T; T x, y; RationalBase() : x(0), y(1) {} template RationalBase(const T1& _x) : RationalBase(_x, T1{1}) {} template RationalBase(const T1& _x, const T2& _y) : x(_x), y(_y) { assert(y != 0); if (y == -1) x = -x, y = -y; if (y != 1) { T g; if constexpr (internal::is_broadly_integral_v) { if constexpr (sizeof(T) == 16) { g = binary_gcd128(x, y); } else { g = binary_gcd(x, y); } } else { g = gcd(x, y); } if (g != 0) x /= g, y /= g; if (y < 0) x = -x, y = -y; } } // y = 0 の代入も認める static R raw(T _x, T _y) { R r; r.x = _x, r.y = _y; return r; } friend R operator+(const R& l, const R& r) { if (l.y == r.y) return R{l.x + r.x, l.y}; return R{l.x * r.y + l.y * r.x, l.y * r.y}; } friend R operator-(const R& l, const R& r) { if (l.y == r.y) return R{l.x - r.x, l.y}; return R{l.x * r.y - l.y * r.x, l.y * r.y}; } friend R operator*(const R& l, const R& r) { return R{l.x * r.x, l.y * r.y}; } friend R operator/(const R& l, const R& r) { return R{l.x * r.y, l.y * r.x}; } R& operator+=(const R& r) { return (*this) = (*this) + r; } R& operator-=(const R& r) { return (*this) = (*this) - r; } R& operator*=(const R& r) { return (*this) = (*this) * r; } R& operator/=(const R& r) { return (*this) = (*this) / r; } R operator-() const { return raw(-x, y); } R inverse() const { assert(x != 0); R r = raw(y, x); if (r.y < 0) r.x = -r.x, r.y = -r.y; return r; } R pow(long long p) const { R res{1}, base{*this}; while (p) { if (p & 1) res *= base; base *= base; p >>= 1; } return res; } friend bool operator==(const R& l, const R& r) { return l.x == r.x && l.y == r.y; }; friend bool operator!=(const R& l, const R& r) { return l.x != r.x || l.y != r.y; }; friend bool operator<(const R& l, const R& r) { return U{l.x} * r.y < U{l.y} * r.x; }; friend bool operator<=(const R& l, const R& r) { return l < r || l == r; } friend bool operator>(const R& l, const R& r) { return U{l.x} * r.y > U{l.y} * r.x; }; friend bool operator>=(const R& l, const R& r) { return l > r || l == r; } friend ostream& operator<<(ostream& os, const R& r) { os << r.x; if (r.x != 0 && r.y != 1) os << "/" << r.y; return os; } T to_mint(T mod) const { assert(mod != 0); T a = y, b = mod, u = 1, v = 0, t; while (b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return U((u % mod + mod) % mod) * x % mod; } }; using Rational = RationalBase; template struct Binomial { vector fc; Binomial(int = 0) { fc.emplace_back(1); } void extend() { int n = fc.size(); R nxt = fc.back() * n; fc.push_back(nxt); } R fac(int n) { if (n < 0) return 0; while ((int)fc.size() <= n) extend(); return fc[n]; } R finv(int n) { if (n < 0) return 0; return fac(n).inverse(); } R inv(int n) { if (n < 0) return -inv(-n); return R{1, max(n, 1)}; } R C(int n, int r) { if (n < 0 or r < 0 or n < r) return R{0}; return fac(n) * finv(n - r) * finv(r); } R operator()(int n, int r) { return C(n, r); } template R multinomial(const vector& r) { static_assert(is_integral::value == true); int n = 0; for (auto& x : r) { if (x < 0) return R{0}; n += x; } R res = fac(n); for (auto& x : r) res *= finv(x); return res; } template R operator()(const vector& r) { return multinomial(r); } }; // using namespace std; using namespace std; // floor(sqrt(n)) を返す (ただし n が負の場合は 0 を返す) long long isqrt(long long n) { if (n <= 0) return 0; long long x = sqrt(n); while ((x + 1) * (x + 1) <= n) x++; while (x * x > n) x--; return x; } namespace EnumerateQuotientImpl { long long fast_div(long long a, long long b) { return 1.0 * a / b; }; long long slow_div(long long a, long long b) { return a / b; }; } // namespace EnumerateQuotientImpl // { (q, l, r) : forall x in (l,r], floor(N/x) = q } // を引数に取る関数f(q, l, r)を渡す。範囲が左に半開なのに注意 // 商は小さい方から走査する template void enumerate_quotient(T N, const F& f) { T sq = isqrt(N); #define FUNC(d) \ T upper = N, quo = 0; \ while (upper > sq) { \ T thres = d(N, (++quo + 1)); \ f(quo, thres, upper); \ upper = thres; \ } \ while (upper > 0) { \ f(d(N, upper), upper - 1, upper); \ upper--; \ } if (N <= 1e12) { FUNC(EnumerateQuotientImpl::fast_div); } else { FUNC(EnumerateQuotientImpl::slow_div); } #undef FUNC } /** * @brief 商の列挙 */ /** * S(f, n) = f(1) + f(2) + ... + f(n) とする * f と g のディリクレ積を h とする * S(h, n) と S(g, n) が高速に計算できる, かつ g(1) = 1 のとき * S(f, N/i) を O(N^{3/4}) で列挙できる * * うまくやると O~(N^{2/3}) に落ちたり g(1) != 1 に対応できる * https://codeforces.com/blog/entry/54150 */ template struct enumerate_mf_prefix_sum { long long N, sq; const SG sg; const SH sh; vector small, large; T& ref(long long x) { if (x <= sq) { return small[x]; } else if (N <= 1000000000000LL) { return large[1.0 * N / x]; } else { return large[N / x]; } } enumerate_mf_prefix_sum(long long _n, SG _sg, SH _sh) : N(_n), sq(isqrt(N)), sg(_sg), sh(_sh) { small.resize(sq + 1); large.resize(sq + 1); enumerate_quotient(N, [&](long long n, long long, long long) { T& cur = (ref(n) = sh(n)); enumerate_quotient(n, [&](long long q, long long l, long long r) { if (q != n) cur -= ref(q) * (sg(r) - sg(l)); }); }); } T get(long long n) { return ref(n); } T operator()(long long n) { return get(n); } }; /** * @brief 乗法的関数のprefix sum の列挙 */ using namespace Nyaan; // k 番目に小さい pl calc(ll N, ll K) { auto sg = [](int n) -> int { return n; }; auto sh = [](int) -> int { return 1; }; enumerate_mf_prefix_sum moe(N, sg, sh); auto cnt = [&](Rational f) -> ll { ll s = 0; enumerate_quotient(N, [&](ll q, ll l, ll r) { ll x = 0; x += atcoder::floor_sum(r + 1, f.y, f.x, 0); x -= atcoder::floor_sum(l + 1, f.y, f.x, 0); s += x * moe(q); }); return s; }; auto judge = [&](pair f) -> bool { return cnt({f.first, f.second}) >= K; }; auto ans = binary_search_on_stern_brocot_tree(judge, N); return {ans.first, ans.second}; } void q() { inl(N, K); auto g = [](ll n) -> ll { return n; }; auto h = [](ll n) -> ll { return n * (n + 1) / 2; }; enumerate_mf_prefix_sum tot(N, g, h); ll s = tot(N) - 1; trc(s); ll p = -1, q = -1; if (K <= s) { tie(p, q) = calc(N, K); } else if (K == s + 1) { p = q = 1; } else if (K <= s * 2 + 1) { tie(q, p) = calc(N, 2 * s + 1 - (K - 1)); } else { // do nothing } if (p == -1) { out(-1); } else { cout << p << "/" << q << "\n"; } } void Nyaan::solve() { int t = 1; // in(t); while (t--) q(); }