import sys
input = sys.stdin.readline

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        return self.find(x) == self.find(y)

    def get_size(self, x):
        x = self.find(x)
        return self.size[x]
    

N = int(input())
if N == 0:
    print(1)
    exit()
X, Y = [0] * N, [0] * N
for i in range(N):
    X[i], Y[i] = map(int, input().split())

def dist(a, b):
    return (X[a] - X[b]) ** 2 + (Y[a] - Y[b]) ** 2

U = UnionFind(N)
for i in range(N):
    for j in range(i + 1, N):
        if dist(i, j) <= 100:
            U.union(i, j)

L = [[] for i in range(N)]
for i in range(N):
    L[U.find(i)].append(i)

from math import sqrt
ans = 0
for i in range(N):
    for j in range(len(L[i])):
        for k in range(j + 1, len(L[i])):
            ans = max(ans, sqrt(dist(L[i][j], L[i][k])))

print(ans + 2)