package main

import "fmt"

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