#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#define N_MAX 2000002

using namespace std;
typedef long long ll;

const ll MOD = 1000000007;

ll inv[N_MAX],fac[N_MAX],finv[N_MAX];

void init(){
    fac[0]=fac[1]=1;
    finv[0]=finv[1]=1;
    inv[1]=1;
    for(int i=2;i<N_MAX;i++){
        inv[i]=MOD-inv[MOD%i]*(MOD/i)%MOD;
        fac[i]=fac[i-1]*(ll) i%MOD;
        finv[i]=finv[i-1]*inv[i]%MOD;
    }
}

ll inv_(ll n){
    if(n == 1) return 1;
    else return MOD-inv_(MOD%n)*(MOD/n)%MOD;
}

ll comb(ll n, ll r){
  ll ans;
  if(n < r){
      ans = 0;
  }else{
      ans = (fac[n]*finv[r])%MOD;
      ans = (ans*finv[n-r])%MOD;
      ans = (ans+MOD)%MOD;
  }
  return ans;
}

ll M, N, D1, D2;


int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    init();
    cin >> N >> M >> D1 >> D2;
    M--;
    M -= D1*(N-1);
    ll D = D2-D1;
    ll ans = 0;
    for(ll i = 0; i <= N-1; i++){
        ll m = M-(D+1)*i; 
        if(i%2 == 0){
            ans += (comb(m+N, N)*comb(N-1, i))%MOD;
            ans %= MOD;
        }else{
            ans -= (comb(m+N, N)*comb(N-1, i))%MOD;
            ans %= MOD;
        }
    }
    ans += MOD;
    ans %= MOD;
    cout << ans << endl;
}