n = 10005
mod = 10 ** 9 + 7
fact = [1] * (n + 1)
invfact = [1] * (n + 1)
for i in range(1, n):
    fact[i + 1] = ((i+1) * fact[i]) % mod
invfact[n] = pow(fact[n], mod - 2, mod)
for i in range(n - 1, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % mod

def comb(n, r):
    if n < 0 or r < 0 or n - r < 0:
        return 0
    return fact[n] * invfact[r] * invfact[n - r] % mod

def bernoulli(n, mod):
    B = [0] * (n + 1)
    B[0] = 1
    B[1] = (- pow(2, mod - 2, mod)) % mod
    for i in range(2, n, 2):
        inv = invfact[i+1] * fact[i]
        temp = - inv * comb(i + 1, 1) * B[1]
        for k in range(0, i, 2):
            temp -= inv * comb(i + 1, k) * B[k]
            temp %= mod
        B[i] = temp
    return B


N, K = map(int, input().split())
ans = 0
v = pow(N + 1, K + 1, mod)
inv = pow(N + 1, mod - 2, mod)
B = bernoulli(K + 5, mod)
v2 = fact[K + 1]
for i in range(K + 1):
    ans += comb(K + 1, i) * B[i] * v
    v *= inv
    ans %= mod
    v %= mod

ans *= pow(K + 1, mod - 2, mod)
print(ans%mod)