# coding: utf-8
# Your code here!
import sys
read = sys.stdin.read
readline = sys.stdin.readline 
readlines = sys.stdin.readlines

p,k = [int(i) for i in read().split()]


a = 1 # zero
b = 0 # non-zero
MOD = 10**9+7

dp = [1,0,0,0,0]
for i in range(k):
    a,b = ((a+b*(p-1))+a*p+b*(p-1))%MOD, ((a+b*(p-1))+b*(p-1))%MOD
    
print(a)