#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <stdio.h>
using namespace std;
#define int long long
int MOD = 1000000007;
template <typename Int, Int MOD, int N>
struct comb_util {
	std::array<Int, N + 1> fc, ifc;

	comb_util() {
		fc[0] = 1;
		for (int i = 1; i <= N; i++) fc[i] = fc[i - 1] * i % MOD;
		ifc[N] = inv(fc[N]);
		for (int i = N - 1; i >= 0; i--) ifc[i] = ifc[i + 1] * (i + 1) % MOD;
	}

	Int fact(Int n) { return fc[n]; }

	Int inv_fact(Int n) { return ifc[n]; }

	Int inv(Int n) { return pow(n, MOD - 2); }

	Int pow(Int n, Int a) {
		Int res = 1, exp = n;
		for (; a; a /= 2) {
			if (a & 1) res = res * exp % MOD;
			exp = exp * exp % MOD;
		}
		return res;
	}

	Int perm(Int n, Int r) {
		if (r < 0 || n < r)
			return 0;
		else
			return fc[n] * ifc[n - r] % MOD;
	}

	Int binom(Int n, Int r) {
		if (n < 0 || r < 0 || n < r) return 0;
		return fc[n] * ifc[r] % MOD * ifc[n - r] % MOD;
	}

	Int homo(Int n, Int r) {
		if (n < 0 || r < 0) return 0;
		return r == 0 ? 1 : binom(n + r - 1, r);
	}
};

using comb = comb_util<long long, 1000000007, 2000100>;
comb cb;
inline int add(int u, int v) {
	u += v;
	if (u >= MOD) u -= MOD;
	return u;
}

inline int sub(int u, int v) {
	u -= v;
	if (u < 0) u += MOD;
	return u;
}

inline int mul(int u, int v) {
	return (long long)u * v % MOD;
}
//0<=Ai<lim, SUM(Ai)=sum
int solve(int n, int sum, int lim) {
	if (n == 0) {
		if (sum == 0) return 1;
		else return 0;
	}
	int res = 0;


	for (int i = 0; i <= n - 2; i++) {
		int sumNow = sum - lim * i;
		if (sumNow < 0) break;
		int foo = cb.binom(n-2, i);
		foo = mul(foo, cb.binom(sumNow + n - 1, n - 1));
		if (i & 1) {
			res = sub(res, foo);
		}
		else {
			res = add(res, foo);
		}
	}

	return res;
}
signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N, M, D1, D2;
	cin >> N >> M >> D1 >> D2;
	int res = solve(N + 1, M - (N - 1) * D1 - 1, D2 - D1 + 1);




	cout << res << endl;
}