#include <bits/stdc++.h>   int main(int argc, char *argv[]) {     int n, i, a, b, c, d;     long int s;     scanf( %d , &n);     s = 0;     for (i = 1; i <= n; i++) {       scanf( %d %d %d %d , &a, &b, &c, &d);       s = s + (1 + abs(a - c)) * (1 + abs(b - d));     }     printf( %ld , s);     return 0;   }   