import sys
readline = sys.stdin.readline

P, K = map(int, input().split())
mod = 10**9 + 7

dp = [1, 0]

for _ in range(K):
    next_dp = [0, 0]

    next_dp[0] += dp[0] + dp[0] * P
    next_dp[1] += dp[0] * (P-1)

    next_dp[0] += dp[1] * 2
    next_dp[1] += dp[1] * (P-1) * 2

    dp = next_dp
    dp[0] %= mod
    dp[1] %= mod

print(dp[0])