func main()
	var a: int :: cui@inputInt()
	var b: int :: cui@inputInt()
	var c: int :: cui@inputInt()
	var d: int :: cui@inputInt()
	var e: int :: cui@inputInt()
	var ans: int :: lib@max(a - b, a - b + c * (d - e))
	do cui@print("\{ans}\n")
end func