#include using namespace std; #ifdef LOCAL #include "debug.h" #else #define DEBUG(...) #endif template > constexpr T power(T a, long long n, Op op = Op(), T e = {1}) { assert(n >= 0); while (n) { if (n & 1) e = op(e, a); if (n >>= 1) a = op(a, a); } return e; } template struct modular { using m = modular; static constexpr unsigned mod = M; unsigned v; modular(long long x = 0) : v((x %= mod) < 0 ? x + mod : x) {} m operator-() const { return m() -= *this; } m& operator+=(m b) { if ((int)(v += b.v - mod) < 0) v += mod; return *this; } m& operator-=(m b) { if ((int)(v -= b.v) < 0) v += mod; return *this; } m& operator*=(m b) { v = (uint64_t)v * b.v % mod; return *this; } m& operator/=(m b) { return *this *= power(b, mod - 2); } friend m operator+(m a, m b) { return a += b; } friend m operator-(m a, m b) { return a -= b; } friend m operator*(m a, m b) { return a *= b; } friend m operator/(m a, m b) { return a /= b; } friend bool operator==(m a, m b) { return a.v == b.v; } }; using mint = modular; vector fact, inv_fact, minv; void prepare(int n) { fact.resize(n + 1), inv_fact.resize(n + 1), minv.resize(n + 1); for (int i = 0; i <= n; ++i) fact[i] = i ? fact[i - 1] * i : 1; inv_fact[n] = power(fact[n], mint::mod - 2); for (int i = n; i--; ) inv_fact[i] = (i + 1) * inv_fact[i + 1]; for (int i = 1; i <= n; ++i) minv[i] = inv_fact[i] * fact[i - 1]; } mint binom(int n, int k) { if (k < 0 or k > n) return 0; return fact[n] * inv_fact[k] * inv_fact[n - k]; } template <> mint& mint::operator/=(mint b) { return *this *= b.v < minv.size() ? minv[b.v] : power(b, mod - 2); } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n, m; cin >> n >> m; prepare(m); mint res; for (int i = 0; i <= m; ++i) { res += power(-1, i) * binom(m, i) * power(i, n); } cout << res.v << '\n'; }