#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001



int main() {
    
	int N,M;
	cin>>N>>M;
	mint ans= 1;
	rep(i,N*2){
		ans *= M+N*2-i;
		ans /= i+1;
	}
	
	ans *= M;
	ans *= N;
	ans /= 2*N+1;
	
	cout<<ans.val()<<endl;
		
	
    return 0;
}