from collections import *
from itertools import *
from functools import *
from heapq import *
import math,sys
input = sys.stdin.readline
mod = 10**9 + 7
N,K = map(int,input().split())
A = pow(K*(K+3)//2,N,mod)
B = pow(K*(K+1)//2,N,mod)
print((A-B)%mod)