output_description: Print the minimum radius of a circle such that all the N points are inside or
  on it.
  
  Your output will be considered correct if the absolute or relative error from
  our answer is at most 10^{-6}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      x_1 y_1
      :
      x_N y_N
attempt: def dist(a, b):
      return ((a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2) ** 0.5
  
  
  n = int(input())
  data = []
  for i in range(n):
      x, y = map(float, input().split())
      data.append((x, y))
  
  now = (500.0, 500.0)
  move = 1
  for i in range(200000):
      max_dist = 0
      max_dist_point = -1
      for j in range(len(data)):
          d = dist(now, data[j])
          if d > max_dist:
              max_dist = d
              max_dist_point = j
      target = data[max_dist_point]
      now = (now[0] + (target[0] - now[0]) * move, now[1] + (target[1] - now[1]) * move)
      move *= 0.999
  max_dist = 0
  for j in range(len(data)):
      d = dist(now, data[j])
      if d > max_dist:
          max_dist = d
  print(max_dist)
  
problem_description: Statement
  
  Given are N points (x_i, y_i) in a two-dimensional plane.
  
  Find the minimum radius of a circle such that all the points are inside or on
  it.
samples: [{"input": "2\n    0 0\n    1 0", "output": "0.500000000000000000\n    \n\nBoth points are contained in the circle centered at (0.5,0) with a radius of\n0.5.\n\n* * *"}, {"input": "3\n    0 0\n    0 1\n    1 0", "output": "0.707106781186497524\n    \n\n* * *"}, {"input": "10\n    10 9\n    5 9\n    2 0\n    0 0\n    2 7\n    3 3\n    2 5\n    10 0\n    3 7\n    1 9", "output": "6.726812023536805158\n    \n\nIf the absolute or relative error from our answer is at most 10^{-6}, the\noutput will be considered correct."}]