import itertools, math

N = int(eval(input()))

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

ans = 0

for e in itertools.permutations(d):

    temp = 0

    for k in range(len(e)-1):

        temp += math.sqrt((e[k][0] - e[k+1][0])**2 + (e[k][1] - e[k+1][1])**2)

    ans += temp

f = 1

for k in range(2,N+1):

    f *= k



print((ans/f))

N = int(eval(input()))

C = []

for _ in range(N):

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

s = 0

for k in range(N-1):

    for l in range(k+1,N):

        s += ((C[k][0]-C[l][0])**2 + (C[k][1]-C[l][1])**2)**(1/2)



print((s/(N/2)))

import itertools, math

N = int(eval(input()))
d = [list(map(int, input().split())) for k in range(N)]
ans = 0
for e in itertools.permutations(d):
    temp = 0
    for k in range(len(e) - 1):
        temp += math.sqrt((e[k][0] - e[k + 1][0]) ** 2 + (e[k][1] - e[k + 1][1]) ** 2)
    ans += temp
f = 1
for k in range(2, N + 1):
    f *= k
print((ans / f))

N = int(eval(input()))
C = []
for _ in range(N):
    C.append(list(map(int, input().split())))
s = 0
for k in range(N - 1):
    for l in range(k + 1, N):
        s += ((C[k][0] - C[l][0]) ** 2 + (C[k][1] - C[l][1]) ** 2) ** (1 / 2)
print((s / (N / 2)))

-import itertools, math - -d = [list(map(int, input().split())) for k in range(N)] -ans = 0 -for e in itertools.permutations(d): -    temp = 0 -    for k in range(len(e) - 1): -        temp += math.sqrt((e[k][0] - e[k + 1][0]) ** 2 + (e[k][1] - e[k + 1][1]) ** 2) -    ans += temp -f = 1 -for k in range(2, N + 1): -    f *= k -print((ans / f)) +C = [] +for _ in range(N): +    C.append(list(map(int, input().split()))) +s = 0 +for k in range(N - 1): +    for l in range(k + 1, N): +        s += ((C[k][0] - C[l][0]) ** 2 + (C[k][1] - C[l][1]) ** 2) ** (1 / 2) +print((s / (N / 2)))