func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long x1, x2, y1, y2;     cin >> x1 >> y1 >> x2 >> y2;     cout << ((y2 - y1 + 1) >= 0 ? (y2 - y1 + 1) : 0) *                     (((x2 - x1 + 2) / 2) >= 0 ? ((x2 - x1 + 2) / 2) : 0) -                 ((y2 + 1 - y1) / 2 >= 0 ? (y2 + 1 - y1) / 2 : 0);   }   