import math
import itertools
import collections

class DisjointSet(object):
    def __init__(self, n):
        self.parent = list(range(n))
        self.rank = [0] * n
        self.num = n  # number of disjoint sets

    def union(self, x, y):
        self._link(self.find_set(x), self.find_set(y))

    def _link(self, x, y):
        if x == y:
            return
        self.num -= 1
        if self.rank[x] > self.rank[y]:
            self.parent[y] = x
        else:
            self.parent[x] = y
            if self.rank[x] == self.rank[y]:
                self.rank[y] += 1

    def find_set(self, x):
        xp = self.parent[x]
        if xp != x:
            self.parent[x] = self.find_set(xp)
        return self.parent[x]


def read_data():
    N = int(input())
    xy = []
    for n in range(N):
        x, y = map(int, input().split())
        xy.append((x, y))
    return N, xy


def solve(N, xy):
    if N == 0:
        return 1
    if N == 1:
        return 2
    djs = DisjointSet(N)
    for i in range(N-1):
        xi, yi = xy[i]
        for j in range(i+1, N):
            xj, yj = xy[j]
            if (xi-xj)**2 + (yi-yj)**2 <= 100:
                djs.union(i, j)
    n_groups = djs.num
    if n_groups == N:
        return 2
    groups = collections.defaultdict(list)
    for i in range(N):
        groups[djs.find_set(i)].append(i)
    max_dist = -1
    for group in groups.values():
        if len(group) == 1:
            dist = 1
            if dist > max_dist:
                max_dist = dist
        for i, j in itertools.combinations(group, 2):
            xi, yi = xy[i]
            xj, yj = xy[j]
            dist = math.hypot(xi-xj, yi-yj)
            if dist > max_dist:
                max_dist = dist
    return max_dist + 2

N, xy = read_data()
print(solve(N, xy))