import itertools



n = int(eval(input()))

s = [0]*n

for i in range(n):

    s[i] = list(int(x) for x in input().split())



key = [[False]*n for i in range(n)]



for i in range(n):

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

        key[i][j] = ((s[i][0]-s[j][0])**2+(s[i][1]-s[j][1])**2)**0.5

ans = 0

key_permnutation = list(int(x) for x in range(n))

for key_list in itertools.permutations(key_permnutation):

    for i in range(n-1):

        p, q = key_list[i], key_list[i+1]

        p, q = min([p, q]), max([p, q])

        ans += key[p][q]



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

    ans /= i

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

s = [0]*n

for i in range(n):

    s[i] = list(int(x) for x in input().split())



key = [[0]*n for i in range(n)]



ans = 0

for i in range(n):

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

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



ans = ans * 2 / n

print(ans)
import itertools

n = int(eval(input()))
s = [0] * n
for i in range(n):
    s[i] = list(int(x) for x in input().split())
key = [[False] * n for i in range(n)]
for i in range(n):
    for j in range(i + 1, n):
        key[i][j] = ((s[i][0] - s[j][0]) ** 2 + (s[i][1] - s[j][1]) ** 2) ** 0.5
ans = 0
key_permnutation = list(int(x) for x in range(n))
for key_list in itertools.permutations(key_permnutation):
    for i in range(n - 1):
        p, q = key_list[i], key_list[i + 1]
        p, q = min([p, q]), max([p, q])
        ans += key[p][q]
for i in range(1, n + 1):
    ans /= i
print(ans)

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

-import itertools - -key = [[False] * n for i in range(n)] +key = [[0] * n for i in range(n)] +ans = 0 -        key[i][j] = ((s[i][0] - s[j][0]) ** 2 + (s[i][1] - s[j][1]) ** 2) ** 0.5 -ans = 0 -key_permnutation = list(int(x) for x in range(n)) -for key_list in itertools.permutations(key_permnutation): -    for i in range(n - 1): -        p, q = key_list[i], key_list[i + 1] -        p, q = min([p, q]), max([p, q]) -        ans += key[p][q] -for i in range(1, n + 1): -    ans /= i +        ans = ans + ((s[i][0] - s[j][0]) ** 2 + (s[i][1] - s[j][1]) ** 2) ** 0.5 +ans = ans * 2 / n