from itertools import combinations
import sys
input = sys.stdin.readline

for _ in range(int(input())) :
    N: int = int(input())
    P: list[tuple[int, int]] = []
    total_x: int = 0
    total_y: int = 0
    
    for _ in range(N) :
        point: tuple[int, int] = tuple(map(int, input().split()))
        total_x += point[0]
        total_y += point[1]
        P.append(point)
        
    min_length: float = float("inf")
        
    for comb in combinations(range(N), N//2) :
        sum_endPoint_x: int = 0
        sum_endPoint_y: int = 0
        
        for i in comb :
            sum_endPoint_x += P[i][0]
            sum_endPoint_y += P[i][1]
        
        sumVector_x = 2*sum_endPoint_x - total_x
        sumVector_y = 2*sum_endPoint_y - total_y     
        min_length = min((sumVector_x**2 + sumVector_y**2)**0.5, min_length)
    
    print(min_length)