func main()
	var n: int :: cui@inputInt()
	var a: int :: n % 10
	do n :/ 10
	var b: int :: n % 10
	do n :/ 10
	var c: int :: n % 10
	
	var ans: bool :: a + c = b
	do cui@print((ans ?("Yes", "No")) ~ "\n")
end func