#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 template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } //constexpr long long MAX = 5100000; constexpr long long INF = 1LL << 60; constexpr int inf = 1000000007; //constexpr long long mod = 1000000007LL; constexpr long long mod = 998244353LL; const long double PI = acos((long double)(-1)); using namespace std; typedef unsigned long long ull; typedef long long ll; typedef long double ld; constexpr long long MAX = 110001; struct mint { long long x; mint(long long x = 0) :x((x% mod + mod) % mod) {} mint& operator+=(const mint a) { if ((x += a.x) >= mod) x -= mod; return *this; } mint& operator-=(const mint a) { if ((x += mod - a.x) >= mod) x -= mod; return *this; } mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this; } mint operator+(const mint a) const { mint res(*this); return res += a; } mint operator-(const mint a) const { mint res(*this); return res -= a; } mint operator*(const mint a) const { mint res(*this); return res *= a; } mint pow(ll t) const { if (!t) return 1; mint a = pow(t >> 1); a *= a; if (t & 1) a *= *this; return a; } // for prime mod mint inv() const { return pow(mod - 2); } mint& operator/=(const mint a) { return (*this) *= a.inv(); } mint operator/(const mint a) const { mint res(*this); return res /= a; } }; long long fac[MAX], finv[MAX], inv[MAX]; void COMinit() { fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < MAX; i++) { fac[i] = fac[i - 1] * i % mod; inv[i] = mod - inv[mod % i] * (mod / i) % mod; finv[i] = finv[i - 1] * inv[i] % mod; } } mint COM(int n, int k) { if (n < k) return 0; if (n < 0 || k < 0) return 0; return mint(fac[n] * (finv[k] * finv[n - k] % mod) % mod); } int main() { /* cin.tie(nullptr); ios::sync_with_stdio(false); */ COMinit(); ll n, k; scanf("%lld %lld", &n, &k); vector res(k + 1); vector pn(k + 1); for (int i = 0; i <= k; i++) pn[i] = mint(i).pow(n); for (int i = 1; i <= k; i++) { if ((k - i) % 2 == 0) continue; for (int j = 0; j <= i; j++) { if (j % 2 == i % 2) res[i] += pn[j] * COM(i, j); else res[i] -= pn[j] * COM(i, j); } res[i] *= COM(k, i); } mint ans = 0; for (int i = 1; i <= k; i++) if ((k - i) & 1) ans += res[i]; cout << ans.x << "\n"; return 0; }