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

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll;
const int inf = 0x3fffffff; const ll INF = 0x1fffffffffffffff; const double eps=1e-12;
void tostr(ll x,string& res){while(x)res+=('0'+(x%10)),x/=10; reverse(ALL(res)); return;}
template<class T> inline bool chmax(T& a,T b){ if(a<b){a=b;return 1;}return 0; }
template<class T> inline bool chmin(T& a,T b){ if(a>b){a=b;return 1;}return 0; }
//template end

template<unsigned mod>struct mint {
   static int get_mod(){return mod;}
   int val;
   int inv() const{
      int tmp,a=val,b=mod,x=1,y=0;
      while(b)tmp=a/b,a-=tmp*b,swap(a,b),x-=tmp*y,swap(x,y);
      if(x<0)x+=mod; return x;
   }
   mint():val(0){}
   mint(ll x):val(x>=0?x%mod:mod+(x%mod)){}
   mint pow(ll t){mint res=1,b=*this; while(t){if(t&1)res*=b;b*=b;t>>=1;}return res;}
   mint& operator+=(const mint& x){if((val+=x.val)>=mod)val-=mod;return *this;}
   mint& operator-=(const mint& x){if((val+=mod-x.val)>=mod)val-=mod; return *this;}
   mint& operator*=(const mint& x){val=(ll)val*x.val%mod; return *this;}
   mint& operator/=(const mint& x){val=(ll)val*x.inv()%mod; return *this;}
   mint operator+(const mint& x)const{return mint(*this)+=x;}
   mint operator-(const mint& x)const{return mint(*this)-=x;}
   mint operator*(const mint& x)const{return mint(*this)*=x;}
   mint operator/(const mint& x)const{return mint(*this)/=x;}
   bool operator==(const mint& x)const{return val==x.val;}
   bool operator!=(const mint& x)const{return val!=x.val;}
};
using Mint=mint<1000000007>;
struct factorial {
   vector<Mint> Fact, Finv;
public:
   factorial(int maxx){
      Fact.resize(maxx+1),Finv.resize(maxx+1); Fact[0]=Mint(1); rep(i,0,maxx)Fact[i+1]=Fact[i]*(i+1);
      Finv[maxx]=Mint(1)/Fact[maxx]; rrep(i,maxx,0)Finv[i-1]=Finv[i]*i;
   }
   Mint fact(int n,bool inv=0){if(inv)return Finv[n];else return Fact[n];}
   Mint nPr(int n,int r){if(n<0||n<r||r<0)return Mint(0);else return Fact[n]*Finv[n-r];}
   Mint nCr(int n,int r){if(n<0||n<r||r<0)return Mint(0);else return Fact[n]*Finv[r]*Finv[n-r];}
};

int main(){
   int N,M,D1,D2; scanf("%d%d%d%d",&N,&M,&D1,&D2);
   int d=D2-D1+1,m=M-D1*(N-1)-1;
   if(m<0){printf("0\n"); return 0;}
   factorial fact(2010000); Mint res;
   rep(i,0,N){
      if(m-d*i+N<0)break;
      Mint add=fact.nCr(N-1,i)*fact.nCr(m-d*i+N,N);
      if(i&1)add*=-1; res+=add;
   }
   printf("%d\n",res.val);
   return 0;
}