#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;

long long mod_pow(long long a, long long e = MOD - 2) {
    long long r = 1;
    for (; e; e >>= 1, a = a * a % MOD) if (e & 1) r = r * a % MOD;
    return r;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    long long N, M;                // 1 ≤ N, M ≤ 1e6
    cin >> N >> M;

    if (N == 1) {                  // 特殊ケース
        long long ans = ((M - 1) % MOD) * mod_pow(2) % MOD;
        cout << ans << '\n';
        return 0;
    }

    long long LIM = N + M;         // ≤ 2e6
    vector<long long> fac(LIM + 1), ifac(LIM + 1);
    fac[0] = 1;
    for (long long i = 1; i <= LIM; ++i) fac[i] = fac[i - 1] * i % MOD;
    ifac[LIM] = mod_pow(fac[LIM]);
    for (long long i = LIM; i; --i) ifac[i - 1] = ifac[i] * i % MOD;

    auto C = [&](long long a, long long b) -> long long {
        if (b < 0 || b > a) return 0;
        return fac[a] * ifac[b] % MOD * ifac[a - b] % MOD;
    };

    long long denom = (C(M + N, N) - N) % MOD;
    if (denom < 0) denom += MOD;

    long long num = 0;
    for (long long k = 1, K = M / N; k <= K; ++k) {
        num += C(M - k * N + N, N);
        if (num >= MOD) num -= MOD;
    }

    long long ans = num * mod_pow(denom) % MOD;
    cout << ans << '\n';
}