201409-2 画图
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 110;
int n;
bool a[N][N];
int main() {
scanf("%d", &n);
while (n--) {
int x1, y1, x2, y2;
scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
for (int i = x1; i < x2; i++)
for (int j = y1; j < y2; j++)
a[i][j] = true;
}
int cnt = 0;
for (int i = 0; i < N; i++)
for (int j = 0; j < N; j++)
if (a[i][j]) cnt++;
printf("%d\n", cnt);
return 0;
}