func main()
	var n: int :: cui@inputInt()
	var k: int :: cui@inputInt()
	const mod: int :: 1000000007
	
	var ans: int :: 0
	do ans :+ math@modPow(n, k, mod)
	do ans :- math@modPow(n - 1, k, mod)
	do ans :+ mod
	do ans :* n
	do ans :% mod
	do cui@print("\{ans}\n")
end func