import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int a = sc.nextInt();
		long total = 0;
		for (int i = 0; i < n; i++) {
		    total += sc.nextInt() - a;
		}
		if (total == 0) {
		    System.out.println("YES");
		} else {
		    System.out.println("NO");
		}
	}
}