n = int(input())
xy = [list(map(int,input().split())) for i in range(n)]
import math
def naga(x1,x2):
    d = math.sqrt((xy[x1][1]-xy[x2][1])**2+(xy[x1][0]-xy[x2][0])**2)
    return d
l = 0
r = naga(0,-1)//10+2
while r>=l:
    mid = (r+l)//2
    visi = [False]*n
    d = []
    d.append(0)
    while d:
        pos = d.pop(0)
        visi[pos] = True
        for i in range(n):
            if i == pos: continue
            if naga(i,pos)<mid*10 and visi[i] == False:
                d.append(i)
    if visi[-1]:
        r = mid-1
    else:
        l = mid+1
print(int(l*10))