#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace atcoder;
using namespace std;
using mint = modint1000000007;
using ll = long long;
const int MAX = 11000000;
const int MOD = 1000000007;

long long fac[MAX], finv[MAX], inv[MAX];
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAX; i++){
        fac[i] = fac[i-1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD;
        finv[i] = finv[i-1] * inv[i] % MOD;
    }
}
long long COM(long long n, long long k){
    if(n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n-k] % MOD) % MOD;
}

int main() {
	ll N, M, D1, D2;cin >> N >> M >> D1 >> D2;
	ll D = D2 - D1;
	ll x =M - (D1 * (N -1)) - 1;
	if (x < 0) {
		cout << 0 << endl;return 0;
	}
	COMinit();
	mint ans = 0;
	for (ll p = 0;p < N;p++) {
		mint tmp = mint(COM(x + N - (p * (D + 1)), N)) * mint(COM(N - 1, p));
		ans += (p % 2 == 0 ? 1 : -1) * tmp;
	}
	
	cout << ans.val() << endl;
}