import java.util.Scanner;
public class Test15 {
	static long kk(long n){
		Scanner sc = new Scanner(System.in);
		long c=0;
		for(int i=0;i<n;i++){
			long s=sc.nextLong();
			c+=s;
		}
		return c;
	}
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s=sc.nextLine();
		String[] s1=s.split(" ");

		long a =Long.parseLong(s1[0]);
		long b =Long.parseLong(s1[1]);
		long d=kk(a);

		if(d%a==0 && d/a==b){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}
}