N, M = map(int, input().split())

mod = 10 ** 9 + 7

m = M + 10

fac = [1] * (m + 1)
facinv = [1] * (m + 1)
for i in range(1, m+1):
    fac[i] = (fac[i-1] * i) % mod
    facinv[i] = (facinv[i-1] * pow(i, -1, mod)) % mod

def nCk(n, k):
    return (fac[n] * facinv[k] * facinv[n-k]) % mod

ans = 0
for i in range(N, M+1):
    ans = (ans + nCk(i, N)) % mod

print(ans)