import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int sample = sc.nextInt();
		
		int sum = 0;
		for (int i = 0; i < n; i++) {
			sum += sc.nextInt();
		}
		
		double avg = (double)sum / n;
		
		if (avg == sample) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}
		sc.close();
	}
}