#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e5+10;
int n;
double rec[2*N],xa,xb,ya,yb;
struct Tree
{
    int l,r,cover;
    double sum;
};
Tree tree[4*N];
struct Line
{
    double l,r,h;
    int flag;
};
Line line[4*N];
int cmp(Line x,Line y)
{
    return x.h<y.h;
}
void build(int node,int L,int R)
{
    tree[node].sum=0;
    tree[node].cover=0;
    tree[node].l=L;
    tree[node].r=R;
    if(L>=R)return ;
    int mid=(L+R)>>1;
    build(2*node,L,mid);
    build(2*node+1,mid+1,R);
}
void Pushup(int node)
{
    if(tree[node].cover)
    {
        tree[node].sum=rec[tree[node].r+1]-rec[tree[node].l];
    }
    else
    {
        if(tree[node].l!=tree[node].r)
        tree[node].sum=tree[2*node].sum+tree[2*node+1].sum;
        else tree[node].sum=0;
    }
}
void update(int node,int L,int R,int x)
{
    if(L<=tree[node].l&&R>=tree[node].r)
    {
        tree[node].cover+=x;
        Pushup(node);
        return ;
    }
    int mid=(tree[node].l+tree[node].r)>>1;
    if(R<=mid)update(2*node,L,R,x);
    else if(L>mid)update(2*node+1,L,R,x);
    else
    {
        update(2*node,L,mid,x);
        update(2*node+1,mid+1,R,x);
    }
    Pushup(node);
}
map<double,int>mp;
int main()
{
    int Case=1;
    while(1)
    {
        scanf("%d",&n);
        if(n==0)break;
        printf("Test case #%d\n",Case++);
        int cnt=1;
        for(int i=0;i<n;i++)
        {
            scanf("%lf%lf%lf%lf",&xa,&ya,&xb,&yb);

            rec[cnt]=line[cnt].l=xa;
            line[cnt].r=xb;
            line[cnt].flag=1;
            line[cnt++].h=ya;

            line[cnt].l=xa;
            rec[cnt]=line[cnt].r=xb;
            line[cnt].h=yb;
            line[cnt++].flag=-1;
        }
        sort(line+1,line+cnt,cmp);
        sort(rec+1,rec+cnt);
        int num=2;
        for(int i=2;i<cnt;i++)
        {
            if(rec[i]!=rec[i-1])rec[num++]=rec[i];
        }
        for(int i=1;i<num;i++)
        {
            mp[rec[i]]=i;
        }
        build(1,1,num-1);
        double ans=0;

        for(int i=1;i<cnt-1;i++)
        {
            int fx=mp[line[i].l];
            int fy=mp[line[i].r];
            update(1,fx,fy-1,line[i].flag);
            ans+=tree[1].sum*(line[i+1].h-line[i].h);
        }
        printf("Total explored area: %.2lf\n",ans);
        printf("\n");
    }
    return 0;
}