from math import sqrt

from itertools import permutations as per

N = int(eval(input()))

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

kumi = per(list(range(N)))

ans = []

leng = 0

for p in kumi:

    cnt = 0

    for i in range(1, len(p)):

        cnt += sqrt((xy[p[i-1]][0] - xy[p[i]][0])**2 + (xy[p[i-1]][1] - xy[p[i]][1])**2)

    ans.append(cnt)

    leng += 1

print((sum(ans) / leng))
N = int(eval(input()))

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



from itertools import permutations

from math import sqrt



paths = list(permutations(list(range(N)), N))

l = len(paths)

total = 0

for path in paths:

    tmp = 0

    x, y = xy[path[0]][0], xy[path[0]][1]

    for p in path[1:]:

        px, py = xy[p][0], xy[p][1]

        tmp += sqrt((px-x)**2 + (py-y)**2)

    total += tmp

print((total / l))
from math import sqrt
from itertools import permutations as per

N = int(eval(input()))
xy = [list(map(int, input().split())) for i in range(N)]
kumi = per(list(range(N)))
ans = []
leng = 0
for p in kumi:
    cnt = 0
    for i in range(1, len(p)):
        cnt += sqrt(
            (xy[p[i - 1]][0] - xy[p[i]][0]) ** 2 + (xy[p[i - 1]][1] - xy[p[i]][1]) ** 2
        )
    ans.append(cnt)
    leng += 1
print((sum(ans) / leng))

N = int(eval(input()))
xy = [list(map(int, input().split())) for i in range(N)]
from itertools import permutations
from math import sqrt

paths = list(permutations(list(range(N)), N))
l = len(paths)
total = 0
for path in paths:
    tmp = 0
    x, y = xy[path[0]][0], xy[path[0]][1]
    for p in path[1:]:
        px, py = xy[p][0], xy[p][1]
        tmp += sqrt((px - x) ** 2 + (py - y) ** 2)
    total += tmp
print((total / l))

-from math import sqrt -from itertools import permutations as per - -kumi = per(list(range(N))) -ans = [] -leng = 0 -for p in kumi: -    cnt = 0 -    for i in range(1, len(p)): -        cnt += sqrt( -            (xy[p[i - 1]][0] - xy[p[i]][0]) ** 2 + (xy[p[i - 1]][1] - xy[p[i]][1]) ** 2 -        ) -    ans.append(cnt) -    leng += 1 -print((sum(ans) / leng)) +from itertools import permutations +from math import sqrt + +paths = list(permutations(list(range(N)), N)) +l = len(paths) +total = 0 +for path in paths: +    tmp = 0 +    x, y = xy[path[0]][0], xy[path[0]][1] +    for p in path[1:]: +        px, py = xy[p][0], xy[p][1] +        tmp += sqrt((px - x) ** 2 + (py - y) ** 2) +    total += tmp +print((total / l))