P8 - Criptanaliza

/**
 * @author Andrei Soceanu
 * @created on 18.06.2018 17:58
*/

#include <iostream>

bool isPrime(unsigned w){
    if (w == 2) return true;
    if (w == 0 || w == 1 || w % 2 == 0) return false;
    for (unsigned i = 3; i < w / 2; i = i + 2)
        if (w % i == 0) return false;
    return true;
}

int main()
{
  unsigned n, k;
  std::cin >> n;
  std::cin >> k;
  int rez = -1;
  for (unsigned i = 0; i < n; i++){
    unsigned w;
    std::cin >> w;
    if (isPrime(w) && w >= k && (w <= rez || rez == -1)) rez = w;
  }
  std::cout << rez << std::endl;
  return 0;
}