#include<bits/stdc++.h>
using namespace std;
 
#define LL long long int
#define rep(i,m) for(i=0;i<m;i++)
#define _ ios_base::sync_with_stdio(0);cin.tie(0);
 
vector<double> myvec;
void push(double a1,double b1,double a2,double b2){
 
 double temp=(double)sqrt((a1-a2)*(a1-a2)+(b1-b2)*(b1-b2));
    myvec.push_back(temp);
    if(myvec.size()>3){sort(myvec.begin(),myvec.end());myvec.erase(myvec.begin()+3);}
}
 
int main()
{_
LL i,j,k,n,t,d,p;
string s1,s2;
cin>>t;j=0;
while(j<t){j++;
 cin>>n;double a[n],b[n];myvec.clear();
 for(i=0;i<n;i++)cin>>a[i]>>b[i];
 for(i=0;i<n;i++)
   for(j=i+1;j<n;j++)
     push(a[i],b[i],a[i+1],b[i+1]);
 
 cout<<"Case "<<j<<": "<<std::setprecision(10)<<myvec[0]+myvec[1]+myvec[0]<<endl;
}
return 0;
}
 

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

MQo0CjAuMCAwLjAKMi4wIDIuMAoyLjAgMC4wCjEuMCAxLjA=

1
4
0.0 0.0
2.0 2.0
2.0 0.0
1.0 1.0