N=int(raw_input())
P=[map(int,raw_input().split()) for i in range(N)]
edge=[[] for i in range(N)]
for i in range(N):
    for j in range(N):
        if i!=j:
            dx=P[i][0]-P[j][0]
            dy=P[i][1]-P[j][1]
            edge[i].append((dx*dx+dy*dy,j))
for i in range(N):
    edge[i].sort()

left = 0
right = 1000000000

while left+1 < right:
    mid=(left+right)/2
    dist=mid*10
    ok=False
    arrived=[False for i in range(N)]
    p=[0]
    arrived[0]=True
    while len(p)!=0:
        cur=p.pop()
        for d,nxt in edge[cur]:
            if d > dist*dist:
                break
            if arrived[nxt]:
                continue
            if nxt==N-1:
                ok=True
                break
            arrived[nxt]=True
            p.append(nxt)
    if ok:
        right = mid
    else:
        left=mid

print right*10