#include<stdio.h>
#include<string.h>
#include<math.h>
const int maxn = 100 + 5;
const int INF = 1e9;
int x[maxn];
int y[maxn];
int vis[maxn];
double low[maxn];
double G[maxn][maxn];
double prim(int n)
{
double res = 0;
double min;
int i,j,pos;
vis[1] = 1;
pos = 1;
for(i = 1; i <= n; i++)
if(i != pos) low[i]=G[pos][i];
for(i=1; i<n; i++)
{
min=INF;
for(j=1; j<=n; j++)
{
if(vis[j]==0&&min>low[j])
{
min=low[j];
pos=j;
}
}
if(min == INF)
break;
res += min;
vis[pos]=1;
for(j=1; j<=n; j++)
if(vis[j]==0 && low[j]>G[pos][j])
low[j]=G[pos][j];
}
if(i != n)
return -1;
return res;
}
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
memset(G,0,sizeof(G));
memset(vis,0,sizeof(vis));
int n,e;
scanf("%d",&n);
for(int i = 1; i <= n; i++)
{
scanf("%d%d",&x[i],&y[i]);
for(int j = 1; j < i; j++)
{
double t = (x[i]-x[j])*(x[i]-x[j]) + (y[i]-y[j])*(y[i]-y[j]);
t = sqrt(t);
if(t >= 10.0 && t <= 1000.0)
G[i][j] = G[j][i] = t;
else
G[i][j] = G[j][i] = INF;
}
}
double ans = prim(n);
ans *= 100;
if(ans > 0)
printf("%.1lf\n",ans);
else
printf("oh!\n");
}
return 0;
}