func_code_string: #include <bits/stdc++.h>   using namespace std;   long long arr[6];   int main() {     for (int i = 0; i < 6; ++i) {       cin >> arr[i];     }     long long res = 0;     for (int i = 0; i < 3; ++i) {       res += arr[i];     }     res *= res;     for (int i = 0; i < 6; i += 2) {       res -= arr[i] * arr[i];     }     cout << res;   }   