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 1 #include<cstdio>
 2 #include<algorithm>
 3 #include<map>
 4 #define lrrt int L,int R,int rt
 5 #define iall 1,n,1
 6 #define imid int mid=(L+R)>>1
 7 #define lson L,mid,rt<<1
 8 #define rson mid+1,R,rt<<1|1
 9 using namespace std;
10 const int M=210;
11 struct line{
12     double left,right,high;
13     int flag;
14     friend bool operator <(line a,line b){
15         return a.high<b.high;
16     }
17 }l[M];
18 double x[M];
19 struct T{
20     int cover;
21     double len;
22 }tree[M<<2];
23 void build(lrrt){
24     tree[rt].cover=0;
25     tree[rt].len=0;
26     if(L==R) return ;
27     imid;
28     build(lson);
29     build(rson);
30 }
31 void pushup(lrrt){
32     if(tree[rt].cover) tree[rt].len=x[R-1]-x[L-2];
33     else if(L==R) tree[rt].len=0;
34     else tree[rt].len=tree[rt<<1].len+tree[rt<<1|1].len;
35 }
36 void update(int x,int y,int val,lrrt){
37     if(x<=L&&R<=y){
38         tree[rt].cover+=val;
39         pushup(L,R,rt);
40         return ;
41     }
42     imid;
43     if(mid>=x) update(x,y,val,lson);
44     if(mid<y)  update(x,y,val,rson);
45     pushup(L,R,rt);
46 }
47 map<double,int> toid;
48 int main(){
49     int n,cas=1;
50     while(~scanf("%d",&n),n){
51         int lx=0;
52         int len=0;
53         while(n--){
54             double x1,y1,x2,y2;
55             scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
56             x[lx++]=x1;
57             x[lx++]=x2;
58             l[len].left=x1;
59             l[len].right=x2;
60             l[len].high=y1;
61             l[len].flag=-1;
62             len++;
63             l[len].left=x1;
64             l[len].right=x2;
65             l[len].high=y2;
66             l[len].flag=1;
67             len++;
68         }
69         sort(x,x+lx);
70         sort(l,l+len);
71         n=unique(x,x+lx)-x;
72         build(iall);
73         toid.clear();
74         for(int i=0;i<n;i++){
75             toid[x[i]]=i+1;
76         }
77         double ans=0;
78         for(int i=0;i<len-1;i++){
79             int s=toid[l[i].left];
80             int e=toid[l[i].right];
81             update(s+1,e,l[i].flag,iall);
82             ans+=(l[i+1].high-l[i].high)*tree[1].len;
83         }
84         printf("Test case #%d\nTotal explored area: %.2f\n\n",cas++,ans);
85     }
86     return 0;
87 }