/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2022.07.30 01:10:27
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;


ll powMod(ll k, ll n, ll mod) {
    ll x = 1;
    while (n > 0) {
        if (n & 1) {
            x = x * k % mod;
        }
        k = k * k % mod;
        n >>= 1;
    }
    return x;
}

ll comb(ll n, ll r, ll mod) {
    ll ret = 1;
    while (true) {
        if (r == 0) break;
        ll N = n % mod;
        ll R = r % mod;
        if (N < R) return 0;
        for (int i = 0; i < R; i++)
        {
            ret = ret * (N - i) % mod;
        }
        ll imul = 1;
        for (int i = 0; i < R; i++)
        {
            imul = imul * (i + 1) % mod;
        }
        ret = ret * powMod(imul, mod - 2, mod) % mod;
        n /= mod; r /= mod;
    }
    return ret;
}

int main() {
    int a,b;cin >> a >> b;
    cout << comb(a+b-2,a-1,998244353) << endl;
    return 0;
}