#include<cstdio>
#include<cmath>
#include<vector>
#include<queue>
using namespace std;
const int MAXN=105;
const double INF=1.0e9;
typedef pair<double,int> P;
struct Point{
    int x,y;
}ps[MAXN];
int V;
vector<int> G[MAXN];
double mp[MAXN][MAXN];
int par[MAXN];
int rnk[MAXN];
double dist(int x1,int y1,int x2,int y2)
{
    return sqrt(double((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
}

void prep(int n)
{
    for(int i=0;i<=n;i++)
    {
        par[i]=i;
        rnk[i]=0;
    }
}

int fnd(int x)
{
    if(par[x]==x)
        return x;
    return par[x]=fnd(par[x]);
}

void unite(int x,int y)
{
    int a=fnd(x);
    int b=fnd(y);
    if(a==b)
    {
        return ;
    }
    if(rnk[a]<rnk[b])
    {
        par[a]=b;
    }
    else
    {
        par[b]=a;
        if(rnk[a]==rnk[b])    rnk[a]++;
    }
}

bool judge(int n)
{
    int f=fnd(1);
    for(int i=2;i<=n;i++)
        if(f!=par[i])    return false;
    return true;
}

double d[MAXN];
int vis[MAXN];
double prim(int s)
{
    double ans=0;
    for(int i=1;i<=V;i++)
    {
        d[i]=INF;
        vis[i]=0;
    }
    d[s]=0;
    priority_queue<P,vector<P>,greater<P> > que;
    que.push(P(0,s));
    
    while(!que.empty())
    {
        P now=que.top();que.pop();
        int v=now.second;
        if(vis[v])    continue;
        ans+=now.first;
        vis[v]=1;
        for(int i=0;i<G[v].size();i++)
        {
            int to=G[v][i];
            if(d[to]>mp[v][to])
            {
                d[to]=mp[v][to];
                que.push(P(d[to],to));    
            }
        }    
    }
    return ans;
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&V);
        prep(V);
        for(int i=1;i<=V;i++)
            for(int j=1;j<=V;j++)
                if(i==j)    mp[i][j]=0;
                else mp[i][j]=INF;
        for(int i=1;i<=V;i++)
        {
            scanf("%d%d",&ps[i].x,&ps[i].y);
        }
        for(int i=1;i<=V;i++)
            for(int j=i+1;j<=V;j++)
            {
                double co=dist(ps[i].x,ps[i].y,ps[j].x,ps[j].y);
                if(co<10||co>1000)    continue;
                mp[i][j]=mp[j][i]=co;
                G[i].push_back(j);
                G[j].push_back(i);
                unite(i,j);
            }
        if(judge(V))
        {
            double ans=prim(1);
            printf("%0.1lf\n",ans*100);
        }
        else
        {
            printf("oh!\n");
        }    
    }
    
    return 0;
}