n, m = map(int, input().split())

MOD = 10 ** 9 + 7
N = m + 10
fact = [0 for _ in range(N)]
invfact = [0 for _ in range(N)]
fact[0] = 1
for i in range(1, N):
    fact[i] = fact[i - 1] * i % MOD

invfact[N - 1] = pow(fact[N - 1], MOD - 2, MOD)

for i in range(N - 2, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % MOD
def nCk(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return fact[n] * invfact[k] * invfact[n - k] % MOD
        
ans = 0
for i in range(n, m + 1):
    ans += nCk(i, n)
    ans %= MOD
print(ans)