P22467

#include <iostream>
using namespace std;

int sum_digits(int n) {

  int r = 0;
  while (n > 0) {

    r = r + (n%10);
    n = n/10;
  }
  return r;
}

int count_digits(int n) {

  int r = 0;
  int dig = 0;
  while (n > 0) {

    r = r + (n%10);
    n = n/10;
    dig++;
  }
  return dig;
}

bool prime(int a) {

    if (a <= 1) return false;
    for (int i = 2; i*i <= a; ++i) {
        if (a%i == 0) return false;
    }
    return true;
}

bool is_perfect_prime (int n) {

  if (not prime(n)) return false;
  int sd = sum_digits(n);
  int cd = count_digits(n);
  bool z = prime(sd); //chek if the sum of the digits is prime
  if (z and cd == 1) return true;
  else if (z) return is_perfect_prime(sd); //recursion: if the number of digits is not 1
                       //repeat the process for the sum of digits
  else return false;

}

int main() {

  int n;
  while (cin >> n) {
    if (is_perfect_prime(n) == true) cout << "true" << endl;
    if (is_perfect_prime(n) == false) cout << "false" << endl;
  }
}