import sys

input = sys.stdin.buffer.readline

N = int(input())
xy = []
zw = []

sx = 0
sy = 0
sz = 0
sw = 0

for _ in range(N):
    x, y = map(int, input().split())
    xy.append((x, y))
    sx += x
    sy += y
for _ in range(N):
    z, w = map(int, input().split())
    zw.append((z, w))
    sz += z
    sw += w

gx = sx / N
gy = sy / N
gz = sz / N
gw = sw / N

distance_xy = 0
distance_zw = 0
for i in range(N):
    distance_xy += ((gx - xy[i][0]) ** 2 + (gy - xy[i][1]) ** 2) ** 0.5
    distance_zw += ((gz - zw[i][0]) ** 2 + (gw - zw[i][1]) ** 2) ** 0.5

print(distance_zw / distance_xy)