func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     unsigned long long t;     cin >> t;     while (t--) {       unsigned long long x1, x2, y1, y2;       cin >> x1 >> y1 >> x2 >> y2;       if (x1 == x2 || y1 == y2) {         cout << 1 <<   n ;       } else {         unsigned long long d = x2 - x1;         unsigned long long r = y2 - y1;         cout << d * r + 1 <<   n ;       }     }     return 0;   }   