#include <stdio.h>

int main(void){

	int n,x[10],i,A=0;
	double a;

	scanf("%d %d",&n,&a);

	for(i=0;i<n;i++){
		scanf("%d",&x[i]);
		A=A+x[i];
	}	

	if(a == (double)(A/n))	printf("YES");
	else		printf("NO");

	return 0;
}