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();
	double x =0;
	double ans = 0;
	for( int i = 0; i < n; i++ ){
		x = sc.nextInt();
		ans += x;
	}
	if( ans / n == a ) System.out.println("YES");
	else System.out.println("No");
	sc.close();
    }
}