#include <bits/stdc++.h>
#include <atcoder/modint>
using mint = atcoder::modint998244353;
using namespace std;
using ll = long long;

mint comb(int n, int k) {
    if (n < k || k < 0) return 0;
    mint t = 1;
    k = min(k, n - k);
    for (int i = 2; i <= k; i++) {
        t *= i;
    }
    t = t.inv();
    for (int i = n - k + 1; i <= n; i++) {
        t *= i;
    }
    return t;
}

int main() {
    int n, m;
    cin >> n >> m;

    mint x = comb(m + n * 2, m) * m / (n * 2 + 1) * n;
    cout << x.val() << endl;

    return 0;
}