#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

#define fi first
#define se second
#define repl(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define rep(i,n) repl(i,0,n)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define mmax(x,y) (x>y?x:y)
#define mmin(x,y) (x<y?x:y)
#define maxch(x,y) x=mmax(x,y)
#define minch(x,y) x=mmin(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt __builtin_popcountll

#define INF 1e16
#define mod 1000000007

ll mod_pow(ll a,ll n){
  ll res=1;
  while(n>0){
    if(n&1)res=res*a%mod;
    a=a*a%mod;
    n>>=1;
  }
  return res;
}

ll fac[2000010],finv[2000010];
ll comb(ll n,ll r){
  if(n<0||r<0||n<r)return 0;
  else return (fac[n]*finv[r]%mod)*finv[n-r]%mod;
}

ll n,m,d1,d2;

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  fac[0]=1;
  rep(i,2000000)fac[i+1]=fac[i]*(i+1)%mod;
  rep(i,2000001)finv[i]=mod_pow(fac[i],mod-2);

  cin>>n>>m>>d1>>d2;
  ll d=d2-d1; m-=(n-1)*d1+1;

  if(m<0){
    cout<<0<<endl;
    return 0;
  }

  ll res=0;
  rep(i,n){
    ll r=m-i*(d+1);
    if(r<0)continue;

    ll c1=comb(n-1,i);
    ll c2=comb(r+n,r);
    ll add=c1*c2%mod;

    if(i%2==0)res+=add;
    else res+=mod-add;
    res%=mod;
  }
  cout<<res<<endl;

  return 0;
}