// #pragma GCC optimize ("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
#include <bits/stdc++.h>

using std::cin, std::cout, std::cerr;
using ll = long long;

const ll P = 998244353;
ll Pow(ll a, ll b) {
    ll r = 1;
    for(; b; b /= 2) {
        if(b & 1)
            r = r * a % P;
        a = a * a % P;
    }
    return r;
}
ll Inv(ll x) { return Pow(x, P - 2); }
struct Comb {
    std::vector<ll> inv, fac, ifac;
    Comb(int n) { Init(n); }
    void Init(int n) {
        inv.assign(n + 1, 0);
        fac.assign(n + 1, 0);
        ifac.assign(n + 1, 0);
        fac[0] = ifac[0] = 1;
        for(int i = 1; i <= n; i ++) {
            inv[i] = i == 1 ? 1 : (P - P / i) * inv[P % i] % P;
            fac[i] = fac[i - 1] * i % P;
            ifac[i] = ifac[i - 1] * inv[i] % P;
        }
    }

    ll Binom(int n, int m) {
        if(m < 0 || n < m) return 0;
        return fac[n] * ifac[m] % P * ifac[n - m] % P;
    }

    ll StirlingPartition(int n, int m) {
        ll ret = 0;
        for(int k = m; k >= 0; k --) {
            int sgn = (m - k) % 2 == 0 ? 1 : P - 1;
            ret += sgn * Binom(m, k) % P * Pow(k, n);
            ret %= P;
        }
        return ret * Inv(fac[m]) % P;
    }
}comb(1e6 + 1);

int main() {
    std::ios::sync_with_stdio(false);
    int n, m, a, b; cin >> n >> m >> a >> b;
    ll ans = 0;
    for(int i = a; i <= b; i ++) {
        ll c = i - ll(n - 1) * (a - 1);
        if(c + 1 < n) continue;
        ans += comb.Binom(c + 1 - 2, n - 2) * comb.fac[n] % P * (m - i);
        ans %= P;
    }
    cout << ans << '\n';
}