n = gets.to_i
x = []
y = []
n.times do |i|
  x[i], y[i] = gets.chomp.split(" ").map(&:to_f)
end
max_dist = 0
for i in 0..n-2
  for j in i+1..n-1
    dist2 = (x[i] - x[j]) ** 2.0 + (y[i] - y[j]) ** 2.0
    max_dist = dist2 if dist2 > max_dist
  end
end
puts (max_dist ** 0.5) / 2.0