import java.util.Scanner;

public class Sample01 {

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