from math import sqrt


class UnionFind:
    def __init__(self, n: int):
        self.data = [-1] * (n+1)
        self.nexts = [i for i in range(n+1)]

    def root(self, a: int) -> int:
        if self.data[a] < 0: return a
        self.data[a] = self.root(self.data[a])
        return self.data[a]

    def unite(self, a: int, b: int) -> bool:
        pa = self.root(a)
        pb = self.root(b)
        if pa == pb: return False
        if self.data[pa] > self.data[pb]:
            pa, pb = pb, pa
        self.data[pa] += self.data[pb] # pa を pb をつなげる
        self.data[pb] = pa
        self.nexts[pa], self.nexts[pb] = self.nexts[pb], self.nexts[pa]
        return True

    def issame(self, a: int, b: int) -> bool:
        return self.root(a) == self.root(b)

    def size(self, a: int) -> int:
        """a が属する集合のサイズ"""
        return -self.data[self.root(a)]

    def group(self, a: int):
        """a が属する集合"""
        yield a
        x = a
        while self.nexts[x] != a:
            x = self.nexts[x]
            yield x


def dist2(a, b):
    return (a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2


N = int(input())
ps = []
for _ in range(N):
    X, Y = map(int, input().split())
    ps.append((X, Y))

uf = UnionFind(N)
for i in range(N):
    for j in range(i+1, N):
        d = dist2(ps[i], ps[j])
        if d <= 10**2:
            uf.unite(i, j)

ans = 1 if N == 0 else 2
for i in range(N):
    for j in range(i+1, N):
        if uf.issame(i, j):
            d = sqrt(dist2(ps[i], ps[j]))
            ans = max(ans, d + 2)

print(ans)