import numpy as np
from scipy.spatial.distance import cdist
from scipy.sparse.csgraph import connected_components

N = int(input())
if N == 0:
    print(1)
    exit()

XY = [tuple(map(int, input().split())) for _ in range(N)]
D = cdist(XY, XY)
p, labels = connected_components(D <= 10)

groups = [[] for _ in range(p)]
for i, x in enumerate(labels):
    groups[x].append(i)

print(max(D[np.ix_(g, g)].max() for g in groups) + 2)