func_code_string: #include <bits/stdc++.h>   const long base = 151;   const long long MM = 1ll * 1000000007 * 1000000007;   using namespace std;   int BIT(int i, long long x) { return (x & (1 << i)); }   long long ONBIT(int i, long long x) { return (x | (1 << i)); }   long long OFFBIT(int i, long long x) { return (x & ~(1 << i)); }   long long FLIPBIT(int i, long long x) { return (x ^ (1 << i)); }   long long NUMBIT(long long x) { return __builtin_popcount(x); }   template <class T>   T GCD(T a, T b) {     T r;     while (b != 0) {       r = a % b;       a = b;       b = r;     }     return a;   }   template <class T>   T LCM(T a, T b) {     return a / GCD(a, b) * b;   }   void read() {     int x, y, u, v;     long long ans = 1;     cin >> x >> y >> u >> v;     int s1 = u - x;     int s2 = v - y;     long long tmp = min(s1, s2) - 1;     ans += (tmp + 1) * (abs(s2 - s1) + 1);     ans += (tmp + 1) * tmp;     cout << ans << endl;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(NULL);     cout.tie(NULL);     long te;     cin >> te;     while (te--) read();   }   