#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}
const int mod = MOD;
const int max_n = 2000050;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
  bool operator==(const mint &p) const { return x == p.x; }
  bool operator!=(const mint &p) const { return x != p.x; }
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
using vm=vector<mint>;
using vvm=vector<vm>;
struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
}comb(max_n);


namespace NTT {
    // int32型のmodが取れるFFT。auto c=NTT::mul(a,b,mod)で受け取り。TIME指定。
	// ChineseRemと組み合わせてlong longにもできる
	std::vector<int> tmp;
	size_t sz = 1;
 
	inline int powMod(int n, int p, int m) {
		int res = 1;
		while (p) {
			if (p & 1) res = (ll)res * n % m;
			n = (ll)n * n % m;
			p >>= 1;
		}
		return (int)res;
	}
	inline int invMod(int n, int m) {
		return powMod(n, m - 2, m);
	}
 
	template <int Mod, int PrimitiveRoot>
	struct NTTPart {
		static std::vector<int> ntt(std::vector<int> a, bool inv = false) {
			size_t mask = sz - 1;
			size_t p = 0;
			for (size_t i = sz >> 1; i >= 1; i >>= 1) {
				auto& cur = (p & 1) ? tmp : a;
				auto& nex = (p & 1) ? a : tmp;
				int e = powMod(PrimitiveRoot, (Mod - 1) / sz * i, Mod);
				if (inv) e = invMod(e, Mod);
				int w = 1;
				for (size_t j = 0; j < sz; j += i) {
					for (size_t k = 0; k < i; ++k) {
						nex[j + k] = (cur[((j << 1) & mask) + k] + (ll)w * cur[(((j << 1) + i) & mask) + k]) % Mod;
					}
					w = (ll)w * e % Mod;
				}
				++p;
			}
			if (p & 1) std::swap(a, tmp);
			if (inv) {
				int invSz = invMod(sz, Mod);
				for (size_t i = 0; i < sz; ++i) a[i] = (ll)a[i] * invSz % Mod;
			}
			return a;
		}
		static std::vector<int> mul(std::vector<int> a, std::vector<int> b) {
			a = ntt(a);
			b = ntt(b);
			for (size_t i = 0; i < sz; ++i) a[i] = (ll)a[i] * b[i] % Mod;
			a = ntt(a, true);
			return a;
		}
	};
 
	constexpr int M[] = {1224736769, 469762049, 167772161};
	constexpr int PR[] = {3, 3, 3};
	constexpr int NTT_CONVOLUTION_TIME = 3;
	/*
		X := max(a)*max(b)*max(|a|, |b|) のとき,
		NTT_CONVOLUTION_TIME <- 1: X <         1224736769 = 1.2*10^ 9 ~ 2^30
		NTT_CONVOLUTION_TIME <- 2: X < 575334854091079681 = 5.8*10^17 ~ 2^59
		NTT_CONVOLUTION_TIME <- 3: X < 2^86 (32bit * 32bit * 10^7くらいまで)
	*/
 
	inline void garner(std::vector<int> *c, int mod) {
		if (NTT_CONVOLUTION_TIME == 1) {
			for(auto& x : c[0]) x %= mod;
		}
		else if (NTT_CONVOLUTION_TIME == 2) {
			const int r01 = invMod(M[0], M[1]);
			for (size_t i = 0; i < sz; ++i) {
				c[1][i] = (c[1][i] - c[0][i]) * (ll)r01 % M[1];
				if (c[1][i] < 0) c[1][i] += M[1];
				c[0][i] = (c[0][i] + (ll)c[1][i] * M[0]) % mod;
			}
		}
		else if (NTT_CONVOLUTION_TIME == 3) {
			const int R01 = invMod(M[0], M[1]);
			const int R02 = invMod(M[0], M[2]);
			const int R12 = invMod(M[1], M[2]);
			const int M01 = (ll)M[0] * M[1] % mod;
			for (size_t i = 0; i < sz; ++i) {
				c[1][i] = (c[1][i] - c[0][i]) * (ll)R01 % M[1];
				if (c[1][i] < 0) c[1][i] += M[1];
				c[2][i] = ((c[2][i] - c[0][i]) * (ll)R02 % M[2] - c[1][i]) * R12 % M[2];
				if (c[2][i] < 0) c[2][i] += M[2];
				c[0][i] = (c[0][i] + (ll)c[1][i] * M[0] + (ll)c[2][i] * M01) % mod;
			}
		}
	}
	std::vector<int> mul(std::vector<int> a, std::vector<int> b, int mod) {
		for (auto& x : a) x %= mod;
		for (auto& x : b) x %= mod;
 
		size_t m = a.size() + b.size() - 1;
		sz = 1;
		while (m > sz) sz <<= 1;
		tmp.resize(sz);
		a.resize(sz, 0);
		b.resize(sz, 0);
 
		std::vector<int> c[NTT_CONVOLUTION_TIME];
		if (NTT_CONVOLUTION_TIME >= 1) c[0] = NTTPart<M[0], PR[0]>::mul(a, b);
		if (NTT_CONVOLUTION_TIME >= 2) c[1] = NTTPart<M[1], PR[1]>::mul(a, b);
		if (NTT_CONVOLUTION_TIME >= 3) c[2] = NTTPart<M[2], PR[2]>::mul(a, b);
		for (auto& v : c) v.resize(m);
		garner(c, mod);
		return c[0];
	}
}; // !!! CHECK NTT_CONVOLUTION_TIME !!!

int main(){
  ll n,m;cin >> n >> m;
  ll x,y;cin >> x >> y;
  m-=x*(n-1);y-=x;
  if(m<=0){
    cout << 0 << endl;return 0;
  }
  vector<int> dp(m);
  ll cnt=0;
  for(ll i=0;i<m;i+=y+1){
    if(cnt&1)dp[i]=(int)((comb(n-1,cnt)*-1).x);
    else dp[i]=(int)((comb(n-1,cnt)).x);
    cnt++;
  }
  vector<int> ndp(m);
  for(ll i=0;i<m;i++){
    ndp[i]=(int)comb(n-2+i,n-2).x;
  }
  vector<int> sdp(m,1);
  //rep(i,m)cout << dp[i] <<" ";cout << endl;
  //rep(i,m)cout << ndp[i] <<" ";cout << endl;
  //rep(i,m)cout << sdp[i] <<" ";cout << endl;
  auto f=NTT::mul(dp,ndp,MOD);
  f=NTT::mul(f,sdp,MOD);
  mint ans=0;
  for(ll i=0;i<m;i++)ans+=f[i];
  cout << ans << endl;
}