1 #include<cstdio>
  2 #include<cstdlib>
  3 #include<cstring>
  4 #include<iostream>
  5 #include<algorithm>
  6 #include<cmath>
  7 using namespace std;
  8 #define Maxn 100010
  9
 10 struct hp
 11 {
 12     int x1,x2,flag;
 13     double y;
 14 }t[Maxn*2];int tl;
 15 struct lsh
 16 {
 17     double x;
 18     int id;
 19 }q[Maxn*2];int ql;
 20
 21 bool cmp(lsh x,lsh y) {return x.x<y.x;}
 22 bool cmp2(hp x,hp y) {return x.y<y.y;}
 23
 24 double dis[2*Maxn];
 25
 26 struct node
 27 {
 28     int l,r,lc,rc,cnt;
 29     double sm;
 30 }tr[Maxn*2];int len;
 31 int build(int l,int r)
 32 {
 33     int x=++len;
 34     tr[x].l=l;tr[x].r=r;
 35     tr[x].sm=tr[x].cnt=0;
 36     if(l<r-1)
 37     {
 38         int mid=(tr[x].l+tr[x].r)>>1;
 39         tr[x].lc=build(l,mid);
 40         tr[x].rc=build(mid,r);
 41     }
 42     else tr[x].lc=tr[x].rc=0;
 43     return x;
 44 }
 45
 46 void upd(int x)
 47 {
 48     int l=tr[x].l,r=tr[x].r;
 49     if(tr[x].cnt!=0) tr[x].sm=dis[r]-dis[l];
 50     else tr[x].sm=tr[tr[x].lc].sm+tr[tr[x].rc].sm;
 51 }
 52
 53 void change(int x,int l,int r,int c)
 54 {
 55     if(tr[x].l==l&&tr[x].r==r)
 56     {
 57         tr[x].cnt+=c;
 58         upd(x);
 59         return;
 60     }
 61     int mid=(tr[x].l+tr[x].r)>>1;
 62     if(r<=mid) change(tr[x].lc,l,r,c);
 63     else if(l>=mid) change(tr[x].rc,l,r,c);
 64     else
 65     {
 66         change(tr[x].lc,l,mid,c);
 67         change(tr[x].rc,mid,r,c);
 68     }
 69     upd(x);
 70 }
 71
 72 int main()
 73 {
 74     int n,kase=0;
 75     while(1)
 76     {
 77         scanf("%d",&n);
 78         if(n==0) break;
 79         tl=0;ql=0;
 80         for(int i=1;i<=n;i++)
 81         {
 82             double x1,y1,x2,y2;
 83             scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
 84             //t[++tl].x1,
 85             t[++tl].flag=1;t[tl].y=y1;
 86             t[++tl].flag=-1;t[tl].y=y2;
 87             q[++ql].x=x1,q[ql].id=tl;
 88             q[++ql].x=x2,q[ql].id=tl+2*n;
 89         }
 90         sort(q+1,q+1+ql,cmp);
 91         int p=0;
 92         for(int i=1;i<=ql;i++)
 93         {
 94             if(q[i].x!=q[i-1].x||p==0) p++,dis[p]=dis[p-1]+q[i].x-q[i-1].x;
 95             if(q[i].id<=2*n) t[q[i].id].x1=t[q[i].id-1].x1=p;
 96             else t[q[i].id-2*n].x2=t[q[i].id-1-2*n].x2=p;
 97         }
 98         sort(t+1,t+1+tl,cmp2);
 99         len=0;tr[0].sm=0;
100         build(1,p);
101         double ans=0;
102         for(int i=1;i<tl;i++)
103         {
104             change(1,t[i].x1,t[i].x2,t[i].flag);
105             ans+=tr[1].sm*(t[i+1].y-t[i].y);
106         }
107         printf("Test case #%d\nTotal explored area: %.2lf\n\n",++kase,ans);
108     }
109     return 0;
110 }