#include using namespace std; using ll = long long; template using vec = vector; template using vvec = vector>; template using vvvec = vector>; constexpr ll mod = 998244353; struct mint { ll x; mint(ll x=0):x((x%mod+mod)%mod){} friend ostream &operator<<(ostream& os,const mint& a){ return os << a.x; } friend istream &operator>>(istream& is,mint& a){ ll t; is >> t; a = mint(t); return (is); } 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; } }; class combination{ private: vector fact,inv,finv; public: combination(int N){ fact = inv = finv = vector(N+1); fact[0] = fact[1] = 1; inv[0] = inv[1] = 1; finv[0] = finv[1] = 1; for(ll i=2;i<=N;i++){ fact[i] = fact[i-1]*i; inv[i] = (mint) mod - inv[mod%i]*(mod/i); finv[i] = finv[i-1]*inv[i]; } } mint f(int i){ return fact[i]; } mint comb(int n,int k){ if(n> N >> M; vec dp(M+1); dp[0] = 1; for(int i=0;i