import math

import itertools



n=int(eval(input()))

d=[list(map(int,input().split())) for _ in range(n)]



ans=cnt=0

for i in itertools.permutations([_ for _ in range(n)]):

  for j in range(n-1):

    x1,x2=d[i[j]][0],d[i[j+1]][0]

    y1,y2=d[i[j]][1],d[i[j+1]][1]

    ans+=math.sqrt((x1-x2)**2+(y1-y2)**2)

  cnt+=1

  #print(j,ans,cnt)

print((ans/cnt))
n=int(eval(input()))

d=[list(map(int,input().split())) for _ in range(n)]



ans=cnt=0

for i in range(n):

  for j in range(i+1,n):

    ans+=((d[i][0]-d[j][0])**2+(d[i][1]-d[j][1])**2)**0.5

print((2*ans/n))
import math
import itertools

n = int(eval(input()))
d = [list(map(int, input().split())) for _ in range(n)]
ans = cnt = 0
for i in itertools.permutations([_ for _ in range(n)]):
    for j in range(n - 1):
        x1, x2 = d[i[j]][0], d[i[j + 1]][0]
        y1, y2 = d[i[j]][1], d[i[j + 1]][1]
        ans += math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
    cnt += 1
    # print(j,ans,cnt)
print((ans / cnt))

n = int(eval(input()))
d = [list(map(int, input().split())) for _ in range(n)]
ans = cnt = 0
for i in range(n):
    for j in range(i + 1, n):
        ans += ((d[i][0] - d[j][0]) ** 2 + (d[i][1] - d[j][1]) ** 2) ** 0.5
print((2 * ans / n))

-import math -import itertools - -for i in itertools.permutations([_ for _ in range(n)]): -    for j in range(n - 1): -        x1, x2 = d[i[j]][0], d[i[j + 1]][0] -        y1, y2 = d[i[j]][1], d[i[j + 1]][1] -        ans += math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) -    cnt += 1 -    # print(j,ans,cnt) -print((ans / cnt)) +for i in range(n): +    for j in range(i + 1, n): +        ans += ((d[i][0] - d[j][0]) ** 2 + (d[i][1] - d[j][1]) ** 2) ** 0.5 +print((2 * ans / n))