from heapq import heappop as hpop, heappush as hpush
from decimal import Decimal
def sq_dist(p1, p2):
	return (p1[0]-p2[0])**2+(p1[1]-p2[1])**2
def solve(s, t, L, n):
	MAX = sq_dist(xy[s],xy[t])
	d = [MAX for i in range(n)]
	Q = list()
	d[s] = 0
	hpush(Q,(0,s))
	while Q:
		tmp = hpop(Q)
		if tmp[1] == t:
			break
		for v in L[tmp[1]]:
			if tmp[0] > v[0]:
				tmpd = tmp[0]
			else:
				tmpd = v[0]
			if tmpd < d[v[1]]:
				d[v[1]] = tmpd
				hpush(Q,(tmpd,v[1]))
	return d[t]

N = int(raw_input())
xy = [map(int,raw_input().split()) for i in xrange(N)]
l = [[(sq_dist(xy[i],xy[j]),j) for j in xrange(N) if j != i] for i in xrange(N)]
max_d = Decimal(solve(0,N-1,l,N)).sqrt()
i_d = int(max_d)
print (i_d+(max_d>i_d)+9) / 10 * 10