from itertools import permutations

from math import factorial



n = int(eval(input()))

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



k = factorial(n)



ret = 0

for perm in permutations(xys):

    a, b = perm[0]

    for x, y in perm:

        ret += (((x - a) ** 2 + (y - b) ** 2) ** 0.5)

        a, b = x, y

print((ret / k))

from collections import namedtuple

from math import sqrt



Coordinates = namedtuple('Coordinates', 'idx x y')





def calc_dist(a: Coordinates, b: Coordinates) -> float:

    return sqrt(pow(a.x - b.x, 2) + pow(a.y - b.y, 2))





n = int(eval(input()))



Coods = []

for idx in range(n):

    x, y = list(map(int, input().split()))

    Coods.append(Coordinates(idx=idx, x=x, y=y))



ret = 0

for a in Coods:

    for b_idx in range(a.idx + 1, n):

        if a.idx == b_idx:

            continue

        b = Coods[b_idx]

        ret += calc_dist(a, b)

ret *= 2 / n

print(ret)



# 特定の2点を固定し、それ以外を並べる + 固定順を逆にする

# [oo]ooo... これを4個の要素の並び替えを見なす

# (n-1)! * 2!

# この2点間の移動が含まれる並び順は、(n-1)! * 2!通り

# 各2点間の距離の総和*(n-1)! * 2!通り / n!

# 各2点間の距離の総和*2/n

from itertools import permutations
from math import factorial

n = int(eval(input()))
xys = [tuple(map(int, input().split())) for _ in range(n)]
k = factorial(n)
ret = 0
for perm in permutations(xys):
    a, b = perm[0]
    for x, y in perm:
        ret += ((x - a) ** 2 + (y - b) ** 2) ** 0.5
        a, b = x, y
print((ret / k))

from collections import namedtuple
from math import sqrt

Coordinates = namedtuple("Coordinates", "idx x y")


def calc_dist(a: Coordinates, b: Coordinates) -> float:
    return sqrt(pow(a.x - b.x, 2) + pow(a.y - b.y, 2))


n = int(eval(input()))
Coods = []
for idx in range(n):
    x, y = list(map(int, input().split()))
    Coods.append(Coordinates(idx=idx, x=x, y=y))
ret = 0
for a in Coods:
    for b_idx in range(a.idx + 1, n):
        if a.idx == b_idx:
            continue
        b = Coods[b_idx]
        ret += calc_dist(a, b)
ret *= 2 / n
print(ret)
# 特定の2点を固定し、それ以外を並べる + 固定順を逆にする
# [oo]ooo... これを4個の要素の並び替えを見なす
# (n-1)! * 2!
# この2点間の移動が含まれる並び順は、(n-1)! * 2!通り
# 各2点間の距離の総和*(n-1)! * 2!通り / n!
# 各2点間の距離の総和*2/n

-from itertools import permutations -from math import factorial +from collections import namedtuple +from math import sqrt + +Coordinates = namedtuple("Coordinates", "idx x y") + + +def calc_dist(a: Coordinates, b: Coordinates) -> float: +    return sqrt(pow(a.x - b.x, 2) + pow(a.y - b.y, 2)) + -xys = [tuple(map(int, input().split())) for _ in range(n)] -k = factorial(n) +Coods = [] +for idx in range(n): +    x, y = list(map(int, input().split())) +    Coods.append(Coordinates(idx=idx, x=x, y=y)) -for perm in permutations(xys): -    a, b = perm[0] -    for x, y in perm: -        ret += ((x - a) ** 2 + (y - b) ** 2) ** 0.5 -        a, b = x, y -print((ret / k)) +for a in Coods: +    for b_idx in range(a.idx + 1, n): +        if a.idx == b_idx: +            continue +        b = Coods[b_idx] +        ret += calc_dist(a, b) +ret *= 2 / n +print(ret) +# 特定の2点を固定し、それ以外を並べる + 固定順を逆にする +# [oo]ooo... これを4個の要素の並び替えを見なす +# (n-1)! * 2! +# この2点間の移動が含まれる並び順は、(n-1)! * 2!通り +# 各2点間の距離の総和*(n-1)! * 2!通り / n! +# 各2点間の距離の総和*2/n