import sys
input = sys.stdin.readline

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

DP=[1,0]
for i in range(K):
    NDP=[0,0]

    DP=[DP[0]*P+DP[0]+DP[1]*2,DP[0]*(P-1)+DP[1]*(P-1)*2]
    DP[0]%=mod
    DP[1]%=mod

print(DP[0])