N = 10**5+50
mod = 10**9+7
fac = [1]*(N+1)
finv = [1]*(N+1)
for i in range(N):
    fac[i+1] = fac[i] * (i+1) % mod
finv[-1] = pow(fac[-1], mod-2, mod)
for i in reversed(range(N)):
    finv[i] = finv[i+1] * (i+1) % mod

def cmb1(n, r, mod):
    if r <0 or r > n:
        return 0
    r = min(r, n-r)
    return fac[n] * finv[r] * finv[n-r] % mod

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

if m > n:
    print(0)
    exit()

ans = 0
for i in range(m+1):
    if (m-i)%2 == 0:
        ans += cmb1(m, i, mod)*pow(i, n, mod)
    else:
        ans -= cmb1(m, i, mod)*pow(i, n, mod)
    ans %= mod
print(ans)