///Enta etfsh5t nseet el rank

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")

#include "bits/stdc++.h"
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update

using namespace std;
using namespace __gnu_pbds;

template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,
        tree_order_statistics_node_update>;
#define pb push_back
#define F first
#define S second
#define f(i, a, b) for (int i = a; i < b; i++)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(x) (int)(x).size()
#define mp(x, y) make_pair(x, y)
#define popCnt(x) (__builtin_popcountll(x))
#define int ll

using ll = long long;
using ull = unsigned long long;
using uint = uint32_t;
using ii = pair<int, int>;

const int N = 5e5 + 6, A = 26, LG = 18, MOD = (119 << 23) + 1;
const long double PI = acos(-1);
const long double EPS = 1e-9;
const ll INF = 1e15;

int fast(int b, int e) {
    int res = 1;
    for (; e; e >>= 1, b = b * b % MOD)
        if (e & 1)
            res = res * b % MOD;
    return res;
}

int fact(int n) {
    return (n == 0 ? 1 : n * fact(n - 1) % MOD);
}

int C(int n, int k) {
    if (k > n || k < 0)
        return 0;
    return fact(n) * fast(fact(k), MOD - 2) % MOD * fast(fact(n - k), MOD - 2) % MOD;
}

void doWork() {
    int n, m;
    cin >> n >> m;
    int ans = C(n + m - 2, n - 1);
    ans = ans * ans % MOD;
    ans = (ans + MOD - C(n + m - 2, n - 2) * C(n + m - 2, m - 2) % MOD) % MOD;
    cout << ans << '\n';
}


int32_t main() {
#ifdef ONLINE_JUDGE
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#endif // ONLINE_JUDGE
    int t = 1;
//    cin >> t;
    while (t--)
        doWork();

    return 0;
}