import java.util.*; class No476{ public static void main(String[] args){ Scanner sc = new Scanner(System.in); int N = sc.nextInt(); int a = sc.nextInt(); double sum = 0; double ave = 0; for(int i=0; i<N; i++){ int No = sc.nextInt(); sum += No; ave = sum/N; } if(a == ave){ System.out.println("YES"); }else{ System.out.println("NO"); } } }