#include <iostream>
#include <algorithm>
#include <vector>
#include <complex>
#include <cmath>
#include <random>
#include <cassert>

using namespace std;

const int MOD = 1e9 + 7;
 
struct mint {
  int n;
  mint(int n_ = 0) : n(n_) {}
};
 
mint operator-(mint a) { return a.n == 0 ? 0 : MOD - a.n; }
mint operator+(mint a, mint b) { return (a.n += b.n) >= MOD ? a.n - MOD : a.n; }
mint operator-(mint a, mint b) { return (a.n -= b.n) < 0 ? a.n + MOD : a.n; }
mint operator*(mint a, mint b) { return 1LL * a.n * b.n % MOD; }
mint &operator+=(mint &a, mint b) { return a = a + b; }
mint &operator-=(mint &a, mint b) { return a = a - b; }
mint &operator*=(mint &a, mint b) { return a = a * b; }

mint F[2000001] = {1, 1};
mint R[2000001] = {1, 1};
mint I[2000001] = {0, 1};

mint C(int n, int r) {
  if (n < 0 || r < 0 || n < r) return 0;
  return F[n] * R[n - r] * R[r];
}

mint H(int n, int r) {
  if (n == 0 && r == 0) return 1;
  return C(n + r - 1, r);
}

void init() {
  for (int i = 2; i <= 2000000; i++) {
    I[i] = I[MOD % i] * (MOD - MOD / i);
    F[i] = F[i - 1] * i;
    R[i] = R[i - 1] * I[i];
  }
}

int main() {
  init();
  long long N, M, D1, D2;
  cin >> N >> M >> D1 >> D2;
  long long D = D2 - D1 + 1;
  if (1 + D1 * (N - 1) > M) {
    cout << 0 << endl;
    return 0;
  }
  M -= 1 + D1 * (N - 1);
  // (1-x^D)^{N-1} / (1-x)^{N+1}
  vector<mint> X(M + 1);
  for (int i = 0; i * D <= M; i++) {
    if (i % 2 == 0) {
      X[i * D] += C(N - 1, i);
    } else {
      X[i * D] -= C(N - 1, i);
    }
  }
  mint F;
  for (int i = 0; i <= M; i++) {
    F += X[i] * H(N + 1, M - i);
  }
  cout << F.n << endl;
}