#include <stdio.h>

int main(void){

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

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

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

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

	return 0;
}