#include <iostream> #include <cmath> bool isPrime(int n) { if (n <= 1) { return false; } for (int i = 2; i <= sqrt(n); i++) { if (n % i == 0) { return false; } } return true; } bool isTongTongNum(int n) { for (int i = 2; i <= n - 1; i++) { if (isPrime(i) && n % i == 0 && isPrime(n / i)) { return true; } } return false; } int main() { int n; std::cin >> n; if (isTongTongNum(n)) { std::cout << "It's a Tongtong number." << std::endl; } else { std::cout << "It's not a Tongtong number." << std::endl; } return 0; }