func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     unsigned long long n;     cin >> n;     if (n % 2 == 0) {       cout << n - (n / 2) << endl;     } else {       cout <<  -  << (n + 1) / 2 << endl;     }     return 0;   }   