package main

import . "fmt"

func main() {
	var n,a int64
	Scan(&n,&a)
	a*=n
	for ;n>0;n-- {
		var x int64
		Scan(&x)
		a-=x
	}
	if a==0 {
		Println("YES")
	} else {
		Println("NO")
	}
}