import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val n = sc.nextInt()
    val a = sc.nextLong()*n;
    var total:Long = 0;
    for (i in 1..n) {
        total += sc.nextLong()
    }
    if (a == total) println("YES") else println("NO")

}