class UnionFind:
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n
        self.group = n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return
        self.group -= 1
        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

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

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return self.group

    def all_group_members(self):
        dic = {r:[] for r in self.roots()}
        for i in range(self.n):
            dic[self.find(i)].append(i)
        return dic

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())

n = int(input())
if n == 0:
    print(1)
    exit()
xy = [list(map(int, input().split())) for _ in range(n)]
UF = UnionFind(n)
for i in range(n):
    for j in range(i + 1, n):
        dx = xy[j][0] - xy[i][0]
        dy = xy[j][1] - xy[i][1]
        if dx * dx + dy * dy <= 100:
            UF.union(i, j)
ans = 0
for i in range(n):
    for j in range(i + 1, n):
        if UF.same(i, j):
            dx = xy[j][0] - xy[i][0]
            dy = xy[j][1] - xy[i][1]
            ans = max(ans, (dx * dx + dy * dy) ** 0.5)
print(ans + 2)