#include using namespace std; #include #include using namespace atcoder; using mint = modint998244353; namespace atcoder { ostream &operator<<(ostream &os, mint a) { os << a.val(); return os; } istream &operator>>(istream &is, mint &a) { long long b; is >> b; a = b; return is; } } // namespace atcoder #define REP_(i,n) for(int i=0;i<(n);i++) template struct FormalPowerSeries:vector{ using FPS=FormalPowerSeries; using vector::resize; using vector::size; using vector::at; using vector::assign; using vector::vector; using vector::begin; using vector::end; using vector::back; using vector::pop_back; using value_type=T; void strict(int n){ if(size()>n)resize(n); } void shrink(){ while(size() and back()==0)pop_back(); } FormalPowerSeries(const vector&f){ int n=min(MX,int(f.size())); resize(n); REP_(i,n)at(i)=f[i]; shrink(); } static FPS unit(){ return {1}; } static FPS x(){ return {0,1}; } #pragma region operator FPS operator-()const{ FPS g=*this; for(T&a:g)a=-a; return g; } FPS &operator+=(const FPS&g){ if(size()=MX)return *this=FPS(0); resize(min(MX,int(size())+d)); for(int i=int(size())-1-d;i>=0;i--) at(i+d)=at(i); for(int i=d-1;i>=0;i--)at(i)=0; return *this; } FPS operator<<(const int d)const{ return FPS(*this)<<=d; } FPS&operator>>=(const int d){ if(d>=size())return *this=FPS(0); for(int i=d;i>(const int d)const{ return FPS(*this)>>=d; } #pragma endregion operator FPS pre(int n)const{ if(size()<=n)return *this; return FPS(begin(),begin()+n); } FPS inv(int SZ=MX)const{ assert(size() and at(0)!=0); FPS res(1,at(0).inv()); for(int n=0;(1<=0); if(n==0)return unit(); if(n==1)return *this; FPS now=*this; now.shrink(); if(!now.size())return now; int d; for(d=0;d=(MX+n-1)/n)return FPS(0); now >>= d; d *= n; if(at(0)==1)return exp(n*log(now))<>=1; } return res<=size())return FPS(0); if(d==1)return FPS(1,at(l)); if(d==2)return at(l) + (l+1>1); FPS f2=rec(rec,l+(d>>1),d-(d>>1)); f2 *= g1.pow(d>>1); return f1+f2; }; FPS res = rec(rec,0,size()); FPS dfg=res, g1inv=(differential(g)>>(--z)).inv(), g2pow=FPS::unit(); T factinv=1; for(int i=1;i*m>z)*g1inv; dfg.strict(MX-m*i); (g2pow*=g2).strict(MX-m*i); factinv /= i; res += factinv * (dfg * g2pow) << (m*i); } return res; } T operator()(T a)const{ T res=0,b=1; for(int i=0;i=0;i--){ at(i)*=finv; finv *= i; } } static FPS differential(FPS f){ if(f.size()<=1)return FPS(0); REP_(i,f.size()-1)f[i]=(i+1)*f[i+1]; f.resize(f.size()-1); return f; } static FPS integral(FPS f){ if(f.size()0;i--)f[i]=f[i-1]/i; f[0]=0; return f; } static FPS log(const FPS&f){ assert(f.size() and f[0]==1); return integral(differential(f)/f); } static FPS exp(const FPS f){ if(!f.size())return unit(); assert(f[0]==0); FPS res=unit(); for(int n=0;(1<; int main() { std::ios::sync_with_stdio(false); std::cin.tie(nullptr); long long n, m; std::cin >> n >> m; FPS f(n + 1); for (int i = 0; i <= n; i++) f[i] = i; f /= 1 + f; for (int i = 0; i < f.size(); i++) f[i] *= std::max(m - i + 1, 0LL); f /= 1 - f; std::cout << f[n] << '\n'; }