import sys
def MI(): return map(int,sys.stdin.readline().rstrip().split())


P,K = MI()
mod = 10**9+7

a,b = P+1,2
for _ in range(K-1):
    a,b = (P+1)*a+(P-1)*b,2*a+(2*P-2)*b
    a %= mod
    b %= mod

print(a)