#include <bits/stdc++.h>
 
using namespace std;
#define int double
#define endl "\n"
 
struct Edge {
    int u, v;
    double weight;
    bool operator<(const Edge &other) const {
        return weight < other.weight;
    }
};
 
double dis(pair<double,double> a, pair<double,double> b){
	return sqrt(pow(a.first - b.first, 2) + pow(a.second - b.second, 2));
}
 
int find(int x, vector<int> par){
	if(par[x] == x)return x;
	return find(par[x], par);
}
 
bool join(int x, int y, vector<int> par){
	int u = find(x, par), v = find(y, par);
	if(u == v)return false;
	return true;
}
 
double kruska(int n, vector<pair<double,double>> &points){
	vector<Edge> edges;
	vector<int> par(n + 1);
 
	for(int i = 0; i < n; i++){
		par[i] = i;
		for(int j = i + 1; j < n; j++){
			edges.push_back({i,j,dis(points[i], points[j])});
		}
	}
 
	sort(edges.begin(), edges.end());
 
	int cnt = 0;
	double sum = 0.00;
 
	for(int i = 0; i < edges.size(); i++){
		if(join(edges[i].u, edges[i].v,par)){
			par[edges[i].v] = edges[i].u;
			sum += edges[i].weight;
			cnt++;
			if(cnt == n - 1)break;
		}
	}
	return sum;
}
 
signed main(){
	ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int tc;cin >> tc;
    string s; getline(cin, s);
    while(tc--){
    	int n; cin >> n;
    	vector<pair<double,double>> points(n);
 
		for(int i = 0; i < n; i++){
			cin >> points[i].first >> points[i].second;
		} 
 
		double result = kruska(n ,points);
		cout << fixed << setprecision(2) << result << endl << endl;
	}
	return 0;
}
 

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3

5
1.0 1.0
3.0 1.0
1.0 3.0
5.0 4.0
7.0 7.0

4
1.0 1.0
-1.0 1.0
-1.0 -1.0
1.0 -1.0

6
3.0 3.0
5.0 -2.0
8.0 4.0
12.5 -3.0
-5.0 -1.0
0.0 0.0