n=int(eval(input()))

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

import itertools as it

ans=0

for i in it.permutations(list(range(n)),n):

    x=xy[i[0]][0]

    y=xy[i[0]][1]

    for k in range(1,n):

        j=i[k]

        ans+=((x-xy[j][0])**2+(y-xy[j][1])**2)**0.5

        x=xy[j][0]

        y=xy[j][1]

N=1

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

    N*=i

print((ans/N))

n=int(eval(input()))

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

from itertools import permutations

ans=0

for i in permutations(list(range(n)),n):

    for j in range(1,n):

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

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

    ans/=i

print(ans)



        

n = int(eval(input()))
xy = [list(map(int, input().split())) for _ in range(n)]
import itertools as it

ans = 0
for i in it.permutations(list(range(n)), n):
    x = xy[i[0]][0]
    y = xy[i[0]][1]
    for k in range(1, n):
        j = i[k]
        ans += ((x - xy[j][0]) ** 2 + (y - xy[j][1]) ** 2) ** 0.5
        x = xy[j][0]
        y = xy[j][1]
N = 1
for i in range(1, n + 1):
    N *= i
print((ans / N))

n = int(eval(input()))
xy = [list(map(int, input().split())) for _ in range(n)]
from itertools import permutations

ans = 0
for i in permutations(list(range(n)), n):
    for j in range(1, n):
        ans += (
            (xy[i[j]][0] - xy[i[j - 1]][0]) ** 2 + (xy[i[j]][1] - xy[i[j - 1]][1]) ** 2
        ) ** 0.5
for i in range(1, n + 1):
    ans /= i
print(ans)

-import itertools as it +from itertools import permutations -for i in it.permutations(list(range(n)), n): -    x = xy[i[0]][0] -    y = xy[i[0]][1] -    for k in range(1, n): -        j = i[k] -        ans += ((x - xy[j][0]) ** 2 + (y - xy[j][1]) ** 2) ** 0.5 -        x = xy[j][0] -        y = xy[j][1] -N = 1 +for i in permutations(list(range(n)), n): +    for j in range(1, n): +        ans += ( +            (xy[i[j]][0] - xy[i[j - 1]][0]) ** 2 + (xy[i[j]][1] - xy[i[j - 1]][1]) ** 2 +        ) ** 0.5 -    N *= i -print((ans / N)) +    ans /= i +print(ans)