#include<stdio.h>

#include<vector>

#include<algorithm>

using namespace std;

const int N = ;

struct Line

{

    int l, r, flag;

    double h;

    Line(){}

    Line(int l, int r, int flag, double h):l(l), r(r), flag(flag), h(h) {}

    bool operator<(Line &b) const

    {

        return h<b.h;

    }

};

int n;

vector<double> vec;

vector<Line>line;

struct node

{

    int l, r, flag;

    double len;

};

node tree[N << ];

void build(int l, int r, int k)

{

    tree[k].l = l, tree[k].r = r, tree[k].len = , tree[k].flag = ;

    if(l == r - )

        return;

    int mid = (l + r) >> ;

    build(l, mid, k<<);

    build(mid, r, k<<|);

}

void updata_up(int k)

{

    if(tree[k].flag)

        tree[k].len = vec[tree[k].r-] - vec[tree[k].l-];

    else if (tree[k].l == tree[k].r - )

        tree[k].len = ;

    else

        tree[k].len = tree[k<<].len + tree[k<<|].len;

}

void updata(int l, int r, int k, int x)

{

    if(tree[k].l >= l && tree[k].r <= r)

    {

        tree[k].flag += x;

        updata_up(k);

        return;

    }

    if(tree[k<<].r > l)

        updata(l, r, k<<, x);

    if(tree[k<<|].l < r)

        updata(l, r, k<<|, x);

    updata_up(k);

}

int main()

{

    int cases = ;

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

    {

        vec.clear();

        line.clear();

        double x1[], y1[], x2[], y2[];

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

        {

            scanf("%lf%lf%lf%lf", &x1[i], &y1[i], &x2[i], &y2[i]);

            vec.push_back(x1[i]);

            vec.push_back(x2[i]);

        }

        sort(vec.begin(), vec.end());

        vec.erase(unique(vec.begin(), vec.end()), vec.end());

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

        {

            int x = lower_bound(vec.begin(), vec.end(), x1[i]) - vec.begin() + ;

            int y = lower_bound(vec.begin(), vec.end(), x2[i]) - vec.begin() + ;

            line.push_back(Line(x, y, , y1[i]));

            line.push_back(Line(x, y, -, y2[i]));

        }

        sort(line.begin(), line.end());

        build(, vec.size() + , );

        double ans = ;

        for(int i=; i<line.size(); ++ i)

        {

            if(i != )

                ans += (line[i].h - line[i-].h)*tree[].len;

            updata(line[i].l, line[i].r, , line[i].flag);

        }

        printf("Test case #%d\nTotal explored area: %.2f\n\n", ++ cases, ans);

    }

}