n, m = map(int, input().split())
mod = 10**9 + 7

fact = [1] * (m + 1)
inv = [1] * (m + 1)
finv = [1] * (m + 1)
for i in range(2, m + 1):
    fact[i] = fact[i - 1] * i % mod
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod
def comb(x, y):
    return fact[x] * finv[y] % mod * finv[x - y] % mod

ans = 0
for i in range(n, m + 1):
    ans += comb(i, n)
    ans %= mod
print(ans)