#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
using namespace std;
int arr[100005][2];
 
typedef struct A { long long x, y; }; 
 
int comp(const void *a, const void *b) {
	A *i1, *i2;
	i1=(A*)a; i2=(A*)b;
	if(i1->x > i2->x) return 1;
	if(i1->x == i2->x && i1->y < i2->y) return 1;
	return 0;
}
 
int main() {
	// your code goes here
	int t, n, i;
	double dis;
	A arr[100005];
	scanf("%d", &t);
	while(t--) {
		scanf("%d", &n); 
		for(i=0; i<n; i++) cin>>arr[i].x>>arr[i].y;
		qsort(arr, n, sizeof(A), comp);
		dis=0;
		for(i=1; i<n; i++) dis=dis+sqrt((arr[i].x-arr[i-1].x)*(arr[i].x-arr[i-1].x)+(arr[i].y-arr[i-1].y)*(arr[i].y-arr[i-1].y));
		printf("%.2f\n", dis);
	}
	return 0;
}

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MwoKMgowIDAKMCAxCgozCjAgMAoxIDEKMiAyCgo0CjAgMAoxIDEwCjEgNQoyIDIK

3

2
0 0
0 1

3
0 0
1 1
2 2

4
0 0
1 10
1 5
2 2