#include #pragma GCC optimize("Ofast") using namespace std; using std::cout; using std::cin; using std::endl; using ll=long long; using ld=long double; ll I=1167167167167167167; ll Q=998244353; #define rep(i,a) for (ll i=0;i using _pq = priority_queue, greater>; template ll LB(vector &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();} template ll UB(vector &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();} template bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;} template bool chmax(T &a,const T &b){if(a void So(vector &v) {sort(v.begin(),v.end());} template void Sore(vector &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});} template void print_tate(vector &v) {rep(i,v.size()) cout<0){ a*=2; if(H%a!=0){ H-=a/2; c*=b; c%=z; } b*=b; b%=z; } //ここまで return c; } //おちこんだりもしたけれど、私はげんきです。 int main() { ios::sync_with_stdio(false); cin.tie(nullptr); ll N,M,ans=0; cin>>N>>M; rep(i,M){ if(i==0) continue; ans+=(((i*(M-i))%Q)*(((jyo(i+1,N,Q)-2*jyo(i,N,Q)+jyo(i-1,N,Q))%Q)))%Q; ans%=Q; //cout<