#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>
#include <string.h>

int main()
{
	int num = 0;
	long long int supAvg = 0;
	long long int total = 0;

	scanf("%d", &num);
	scanf("%lld", &supAvg);

	for (int i = 0;i < num;i++)
	{
		long long int a = 0;
		scanf("%lld", &a);
		total += a;
	}

	if (total / (double)num == supAvg)
	{
		printf("YES\n");
		return 0;
	}
	printf("NO\n");

	return 0;
}