is_prime_number.cpp

#include <iostream>

bool is_prime(unsigned long long n) {
  if (n <= 1) return false;
  if (n == 2) return true;
  if (n % 2 == 0) return false;
  for (int i = 3; i * i <= n; i += 2)
    if (n % i == 0) return false;
  return true;
}

int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(nullptr);
  std::cout.tie(nullptr);
  unsigned long long n = 0;
  std::cin >> n;
  std::cout << (is_prime(n) ? "true" : "false") << '\n';
  return 0;
}