/**

* ZOJ 1128 Atlantis

*

* 2005/04/07 By adai

*

* Algo Desc: ÀëÉ¢»¯

*/

#include <iostream>

#include <cstdio>

#include <cmath>

#include <string>

using namespace std;

#ifdef WIN32

#define for if(0); else for

#endif

#define eps 1e-8

class hline {

public:

double left;

double right;

double y;

int type;

}hh[200];

int cmp1(const void *t1, const void *t2) {

double *a, *b;

a = (double*) t1;

b = (double*) t2;

if ((*a) - (*b) > eps) return 1;

if ((*a) - (*b) < eps) return -1;

return 0;

}

int cmp2(const void *t1, const void *t2) {

hline *a, *b;

a = (hline*) t1;

b = (hline*) t2;

if ((*a).y - (*b).y > eps) return 1;

if ((*a).y - (*b).y < eps) return -1;

return 0;

}

double vv[200];

int n;

int numh, numv;

int Run() {

numh = numv = 0;

double left, top, right, bottom;

for (int i = 0; i < n; ++i) {

scanf("%lf %lf %lf %lf", &left, &top, &right, &bottom);

hh[numh].left = left, hh[numh].right = right, hh[numh].y = top, hh[numh++].type = 0;

hh[numh].left = left, hh[numh].right = right, hh[numh].y = bottom, hh[numh++].type = 1;

vv[numv++] = left, vv[numv++] = right;

}

qsort(vv, numv, sizeof(vv[0]), cmp1);

qsort(hh, numh, sizeof(hh[0]), cmp2);

double ret = 0;

int count = 0;

for (int i = 0; i < numv - 1; ++i) {

left = vv[i], right = vv[i + 1];

for (int j = 0; j < numh; ++j) {

if (hh[j].left <= left && hh[j].right >= right) {

bottom = hh[j].y;

if (count > 0) {

ret += (right - left) * (bottom - top);

}

if (hh[j].type) --count;

else ++count;

top = bottom;

}

}

}

printf("Total explored area: %.2lf\n\n", ret);

return 0;

}

int main() {

int kase = 1;

while (scanf("%d", &n) && n) {

printf("Test case #%d\n", kase++);

Run();

}

return 0;

}