import java.util.Scanner;
public class Heikin {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		double n = s.nextDouble();
		double a = s.nextDouble();
		double total = 0;
		for(int i = 0;i < n;i++){
			total += s.nextDouble();;
		}
		s.close();
		if(a == total/n){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}
}