func_code_string: #include <bits/stdc++.h>   using namespace std;   bool Primality(long long n) {     if (n < 2) return false;     if (n == 2) return true;     if (n % 2 == 0) return false;     for (long long i = 3; i * i <= n; i = i + 2)       if (n % i == 0) return false;     return true;   }   int main() {     long long n;     cin >> n;     for (long long i = 1; i <= 1000; i++) {       long long pr = (n * i) + 1;       if (!Primality(pr)) {         cout << i <<   n ;         break;       }     }     return 0;   }   