#include <bits/stdc++.h>

using namespace std;

int cnt=0;

struct co
{
    double x,y;
    int id;
    co(double a,double b)
    {
        id=cnt++;
        x=a;
        y=b;
    }
};

struct edge
{
    int u,v;
    double w;
    edge(int a,int b,double c):u(a),v(b),w(c){}
    bool operator<(const edge& p) const
    {
        return w<p.w;
    }
};

vector<edge> ed;
vector<co> nd;
vector<int> par;

int find_par(int n)
{
    return (n==par[n]) ? n : find_par(par[n]);
}

double mst(int n)
{
    par.clear();
    par.resize(n);
    for(int i=0;i<n;i++) par[i]=i;

    double w=0; int c=0;

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

    int l=ed.size();

    for(int i=0;i<l;i++)
    {
        int a=find_par(ed[i].u);
        int b=find_par(ed[i].v);
        if(a!=b)
        {
            par[b]=a;
            w+=ed[i].w;
            c++;
            if(c==n-1) break;
        }
    }
    return w;
}

int main()
{
    int tc;
    freopen("in.txt","r",stdin);
    while(cin>>tc)
    {
        //scanf("\n");
        while(tc--)
        {
            nd.clear();
            ed.clear();
            int n;
            cin>>n;
            while(n--)
            {
                double a,b;
                cin>>a>>b;
                nd.push_back(co(a,b));
            }
            //scanf("\n");
            n=nd.size();
            for(int i=0;i<n-1;i++)
            {
                int x1=nd[i].x;
                int y1=nd[i].y;
                for(int j=i+1;j<n;j++)
                {
                    int x2=nd[j].x;
                    int y2=nd[j].y;
                    double d=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
                    ed.push_back(edge(nd[i].id,nd[j].id,d));
                }
            }
            printf("%.2lf\n",mst(n));
            if(tc) cout<<endl;
        }
    }
    return 0;
}