import heapq

N=int(input())
P=[tuple(map(int,input().split())) for i in range(N)]

DP=[1<<60]*N
DP[0]=0

Q=[(0,0)]

while Q:
    dis,x=heapq.heappop(Q)

    if DP[x]!=dis:
        continue

    a,b=P[x]

    for i in range(N):
        c,d=P[i]

        d=(a-c)**2+(b-d)**2

        yy=int(d**(1/2))
        score=0

        for j in range(yy-5,yy+5):
            if j<=0:
                continue
            if j*j>=d:
                score=j
                break
        if DP[i]>max(score,DP[x]):
            DP[i]=max(score,DP[x])
            heapq.heappush(Q,(DP[i],i))

print((DP[-1]+9)//10*10)