#include <stdio.h>

typedef struct {
  int n;
  long int a;
  long int x;
  double average;
} checkInfo;

void cal_average(checkInfo *p);
void print_result(checkInfo *p);

int main(void)
{
  checkInfo data;

  scanf("%d %ld", &data.n, &data.a);
  cal_average(&data);
  print_result(&data);

  return 0;
}

void cal_average(checkInfo *data)
{
  data->average = 0;
  for (int i = 0; ~scanf("%ld", &data->x); ++i) 
    data->average += data->x;
  data->average /= data->n;
}

void print_result(checkInfo *data)
{
  printf("%s\n", (data->average == data->a) ? "YES" : "NO");
}