class UnionFind:

    def __init__(self, size):
        # 負の値はルート (集合の代表) で集合の個数
        # 正の値は次の要素を表す
        self.table = [-1 for _ in range(size)]

    def search_group_ids(self):
        ids = []
        for t in self.table:
            if t > -1:
                ids.append(t)
        return ids

    def find(self, x):
        # 集合の代表を求める
        while self.table[x] >= 0:
            x = self.table[x]
        return x

    def union(self, x, y):
        # 併合
        s1 = self.find(x)
        s2 = self.find(y)
        if s1 != s2:
            if self.table[s1] >= self.table[s2]:
                self.table[s1] += self.table[s2]
                self.table[s2] = s1
            else:
                self.table[s2] += self.table[s1]
                self.table[s1] = s2
        return self.table[s1]

N = int(input())
if N==0:
    print(1)
    exit()
if N==1:
    print(2)
    exit()
uf = UnionFind(N)
P = []
for i in range(N):
    x, y = map(int, input().split())
    P.append((y, x))

dist = [[0 for j in range(N)] for i in range(N)]
for i in range(N - 1):
    for j in range(i + 1, N):
        dy = P[i][0] - P[j][0]
        dx = P[i][1] - P[j][1]
        dist[i][j] = dy * dy + dx * dx
        if dist[i][j] <= 100:
            uf.union(i, j)
group = [[]]*N
for i in range(N):
    group[uf.find(i)].append(i)
max_len = 2
for i in range(N):
    l = len(group[i])
    if l<2:
        continue
    for j in range(l-1):
        for k in range(j+1,l):
            max_len = max(max_len, dist[j][k]**0.5+2)
print(max_len)