import java.util.Scanner;

public class Ex1
{
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		int index = scan.nextInt();
		int ave = scan.nextInt();
		int[] number = new int[index];
		int sum=0;
		for(int i=0;i<index;i++){
			number[i] = scan.nextInt();
		}
		for(int i=0;i<index;i++){
			sum += number[i];
		}
		
		double average = sum/(double)index;
		if(average == ave)
			System.out.println("yes");
		else 
			System.out.println("no");
	}
}