N=int(input())

import math

pmin=0
for i in range(N):
    x,y=map(float,input().split())
    if x*x+y*y>0:
        pmin=max(pmin,x*x+y*y)

qmin=0
for i in range(N):
    x,y=map(float,input().split())
    if x*x+y*y>0:
        qmin=max(qmin,x*x+y*y)

ans=qmin/pmin

print(math.sqrt(ans))