#define _GLIBCXX_DEBUG //遅い可能性がある 
#include <bits/stdc++.h>
#include<atcoder/all>
#include<boost/multiprecision/cpp_int.hpp> //多倍長
using namespace boost::multiprecision; // 多倍長.型はcpp_int
using namespace atcoder;
using namespace std;
#define rep(i, n) for (ll i = 0; i < (int)(n); i++)
#define ALL(a) (a).begin(),(a).end() //lower_bound(ALL(a),x)
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<vector<int>>;

ll MOD = 998244353;
int INF = 100100100;

const vector<int> dx = {1, 0, -1, 0};
const vector<int> dy = {0, 1, 0, -1};

int depth[110000];
int mxdepth[110000];

long long modpow(long long a, long long n, long long mod) {
    long long res = 1;
  	if (a == 0) return 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;
        n >>= 1;
    }
    return res;
}



int main() {
    int N,M;
    cin >> N >> M;
    ll ans = N;
    ll n = 2*N+M;
    ll k = 2*N+1;
    rep(i,k){
        ll temp = (n-i) * modpow(i+1,MOD-2,MOD);
        ans *= temp%MOD;
        ans %= MOD;
    }
    cout << ans << endl;
    return 0;
}