package main

import "fmt"

func main() {
	var n, a float64
	fmt.Scan(&n, &a)
	tot := 0.0
	for i := 0; i < int(n); i++ {
		var v float64
		fmt.Scan(&v)
		tot += v
	}
	if tot/n == a {
		fmt.Println("YES")
	} else {
		fmt.Println("NO")
	}
}