N, M, D1, D2 = map(int, input().split())
MOD = 10**9 + 7

num = 2*10**6
frac = [1] * num
inv_frac = [1] * num
for i in range(2, num):
    frac[i] = (frac[i-1] * i) % MOD

inv_frac[-1] = pow(frac[-1], MOD-2, MOD)
for i in range(num-1, 0, -1):
    inv_frac[i-1] = (inv_frac[i] * i) % MOD

def comb(n, r):
    if r < 0 or r > n:
        return 0
    
    return (frac[n] * (inv_frac[n-r] * inv_frac[r])%MOD) % MOD


def calc(n, m):
    # 合計 m個を n人で分ける
    # n人それぞれの最小個数は0個
    # {m+1}_H_{n-1} = {m+n-1}_C_{n-1}
    return comb(n+m-1, n-1)


M = M - 1 - D1*(N-1)
ans = calc(N+1, M)
for k in range(1, N):
    m = M - (D2-D1+1)*k
    ans += (-1)**(k%2) * comb(N-1, k) * calc(N+1, m)
    ans %= MOD

print(ans)