func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int sum = 0;     for (int i = 0; i < n; i++) {       int x1, x2, y1, y2;       cin >> x1 >> x2 >> y1 >> y2;       sum += (max(x1, y1) - min(x1, y1) + 1) * (max(x2, y2) - min(x2, y2) + 1);     }     cout << sum <<   n ;     return 0;   }   