import itertools

import math

n = int(eval(input()))

lis1 = []

for i in range(n):

    lis1.append(list(map(int, input().split())))

S = 0

for i in list(itertools.permutations(list(range(n)))):

    for j in range(n-1):

        S += math.sqrt((lis1[i[j]][0]-lis1[i[j+1]][0])**2 + (lis1[i[j]][1]-lis1[i[j+1]][1])**2)

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

    S = S / i

print(S)
n = int(eval(input()))

lis = []

for i in range(n):

    lis.append(list(map(int, input().split())))

s = 0

for i in range(n):

    for j in range(i,n):

        s += ((lis[i][0] - lis[j][0])**2 + (lis[i][1] - lis[j][1])**2)**(1/2)

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

n = int(eval(input()))
lis1 = []
for i in range(n):
    lis1.append(list(map(int, input().split())))
S = 0
for i in list(itertools.permutations(list(range(n)))):
    for j in range(n - 1):
        S += math.sqrt(
            (lis1[i[j]][0] - lis1[i[j + 1]][0]) ** 2
            + (lis1[i[j]][1] - lis1[i[j + 1]][1]) ** 2
        )
for i in range(1, n + 1):
    S = S / i
print(S)

n = int(eval(input()))
lis = []
for i in range(n):
    lis.append(list(map(int, input().split())))
s = 0
for i in range(n):
    for j in range(i, n):
        s += ((lis[i][0] - lis[j][0]) ** 2 + (lis[i][1] - lis[j][1]) ** 2) ** (1 / 2)
print((s * 2 / n))

-import itertools -import math - -lis1 = [] +lis = [] -    lis1.append(list(map(int, input().split()))) -S = 0 -for i in list(itertools.permutations(list(range(n)))): -    for j in range(n - 1): -        S += math.sqrt( -            (lis1[i[j]][0] - lis1[i[j + 1]][0]) ** 2 -            + (lis1[i[j]][1] - lis1[i[j + 1]][1]) ** 2 -        ) -for i in range(1, n + 1): -    S = S / i -print(S) +    lis.append(list(map(int, input().split()))) +s = 0 +for i in range(n): +    for j in range(i, n): +        s += ((lis[i][0] - lis[j][0]) ** 2 + (lis[i][1] - lis[j][1]) ** 2) ** (1 / 2) +print((s * 2 / n))