#include <bits/stdc++.h>   using namespace std;   bool isPrime(int num) {     for (int i = 2; i <= sqrt(num) + 1; ++i) {       if (num % i == 0) return false;     }     return true;   }   int main() {     int n;     cin >> n;     if (n < 9) {       cout << 1 << endl;       cout << n << endl;     } else if (n == 9) {       cout << 3 << endl;       cout << 3 <<     << 3 <<     << 3 << endl;     } else if (n == 11) {       cout << 3 << endl;       cout << 3 <<     << 3 <<     << 5 << endl;     } else {       cout << 3 << endl;       n -= 3;       for (int i = 3; i <= n / 2; ++i) {         if (isPrime(i) && isPrime(n - i)) {           cout << 3 <<     << i <<     << n - i << endl;           break;         }       }     }     return 0;   }   