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

def dist(a,b):
    return abs(a[0]-b[0])**2+abs(a[1]-b[1])**2

from collections import deque
def bfs(v,graph):
    que=deque();que.append(v)
    dist=[-1]*n;dist[v]=0
    while que:
        v=que.popleft()
        for nv in graph[v]:
            if dist[nv]!=-1:continue    
            dist[nv]=dist[v]+1
            que.append(nv)
    
    return dist

def check(x):
    graph=[[] for _ in range(n)]
    for i in range(n-1):
        for j in range(i+1,n):
            if dist(xy[i],xy[j])<=x**2:
                graph[i].append(j)
                graph[j].append(i)
    
    d=bfs(0,graph)
    return d[-1]!=-1
    

ng,ok=-1,10**18
while ok-ng>1:
    mid=(ok+ng)//2
    if check(10*mid):
        ok=mid
    else:
        ng=mid

print(ok*10)