#include<cstdio>

#include<iostream>

#include<algorithm>

#include<cstring>

#include<cmath>

#include<cctype>

#include<cstdlib>

#include<vector>

#include<queue>

#include<map>

#include<set>

#define ls (tr<<1)

#define rs (tr<<1|1)

#define ull unsigned long long

#define ll long long

#define R register int

using namespace std;

namespace Fread {

    static char B[<<],*S=B,*D=B;

    #define getchar() (S==D&&(D=(S=B)+fread(B,1,1<<15,stdin),S==D)?EOF:*S++)

    inline int g() {

        R ret=,fix=; register char ch; while(!isdigit(ch=getchar())) fix=ch=='-'?-:fix;

        do ret=ret*+(ch^); while(isdigit(ch=getchar())); return ret*fix;

    } inline bool isempty(const char& ch) {return ch<=||ch>=;}

    inline void gs(char* s) {register char ch; while(isempty(ch=getchar())); do *s++=ch; while(!isempty(ch=getchar()));}

}using Fread::g; using Fread::gs;

const int N=;

struct ln {

    double l,r,x; int w; ln() {}

    ln(double Ll,double rr,double xx,int ww) {l=Ll,r=rr,x=xx,w=ww;}

    bool operator < (const ln& that) const {return x<that.x;}

}L[N]; int n,t,tot; double d[N];

int cnt[N<<]; double sum[N<<];

inline void upd(int tr,int l,int r) {

    if(cnt[tr]) sum[tr]=d[r+]-d[l];

    else if(l==r) sum[tr]=;

    else sum[tr]=sum[ls]+sum[rs];

}

inline void change(int tr,int l,int r,int LL,int RR,int vl) {

    if(LL<=l&&r<=RR) {cnt[tr]+=vl; upd(tr,l,r); return ;} R md=l+r>>;

    if(LL<=md) change(ls,l,md,LL,RR,vl); if(RR>md) change(rs,md+,r,LL,RR,vl); upd(tr,l,r);

}

signed main() {

#ifdef JACK

    freopen("NOIPAK++.in","r",stdin);

#endif

    while(scanf("%d",&n),n!=) { memset(cnt,,sizeof(cnt)),memset(sum,,sizeof(sum)); tot=;

        for(R i=;i<=n;++i) { register double l,p,r,b;

            scanf("%lf%lf%lf%lf",&l,&p,&r,&b);

            d[++tot]=l,L[tot]=ln(l,r,p,);

            d[++tot]=r,L[tot]=ln(l,r,b,-);

        } sort(d+,d+tot+),sort(L+,L+tot+);

        n=unique(d+,d+tot+)-d-; register double ans=;

        for(R i=;i<=tot;++i) {

            R l=lower_bound(d+,d+n+,L[i].l)-d;

            R r=lower_bound(d+,d+n+,L[i].r)-d-;

            change(,,n,l,r,L[i].w);

            ans+=sum[]*(L[i+].x-L[i].x);

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

    }

}