MOD = 10 ** 9 + 7
MAX = 10 ** 4 + 10

modinv_table = [None] + [pow(i, -1, MOD) for i in range(1, MAX)]

fac, inv = [1] * MAX, [1] * MAX
for i in range(1, MAX):
    fac[i] = fac[i - 1] * i % MOD
    inv[i] = pow(fac[i], -1, MOD)


def comb(n, k, error=0):
    if not 0 <= k <= n:
        return error
    return fac[n] * inv[k] * inv[n - k] % MOD


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

B = [1]
for i in range(1, K + 1):
    tmp = 0
    for k in range(i):
        tmp += comb(i + 1, k) * B[k]
        tmp %= MOD
    B.append(-tmp * modinv_table[i + 1] % MOD)

ans = 0
for j in range(K + 1):
    ans += comb(K + 1, j) * B[j] * pow(N + 1, K + 1 - j, MOD)
    ans %= MOD
ans *= modinv_table[K + 1]
ans %= MOD
print(ans)