N,M = map(int,input().split())
MOD = 10 ** 9 + 7
fact = [1]*(M+1)
rfact = [1]*(M+1)
r = 1
for i in range(1, M+1):
    fact[i] = r = r * i % MOD
rfact[M] = r = pow(fact[M], -1, MOD)
for i in range(M, 0, -1):
    rfact[i-1] = r = r * i % MOD

# nCk (mod MOD) を求める
def comb(n, k):
    return fact[n] * rfact[k] * rfact[n-k] % MOD
ans = 0
for i in range(N,M+1):
    ans += comb(i,N)
    ans %= MOD
print(ans)