#include <iostream>

int main() {
  unsigned short n;
  unsigned int a;
  unsigned long long int sum = 0;
  double average;

  std::cin >> n >> a;
  for (int i = 0; i < n; i++) {
    unsigned int t;
    std::cin >> t;
    sum += t;
  }
  average = sum / (float)n;
  if (a == average) std::cout << "YES" << std::endl;
  else std::cout << "NO" << std::endl;
  return 0;
}