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 want(x, y):
  
      ret = 0
  
      for i in xy:
          ret = max(ret, ((i[0] - x) ** 2 + (i[1] - y) ** 2) ** 0.5)
  
      return ret
  
  
  def want2(x):
  
      ly = miny
      ry = maxy
  
      while ry - ly > 10 ** (-7) and ry - ly > (ry / (10**6)):
  
          m1 = (ly * 2 + ry) / 3
          m2 = (ly + ry * 2) / 3
  
          rm1 = want(x, m1)
          rm2 = want(x, m2)
  
          if rm1 > rm2:
              ly = m1
          else:
              ry = m2
  
      ansy = (ly + ry) / 2
      return want(x, ansy)
  
  
  N = int(input())
  
  xy = []
  minx = float("inf")
  maxx = float("-inf")
  miny = float("inf")
  maxy = float("-inf")
  
  for i in range(N):
  
      x, y = map(int, input().split())
      xy.append([x, y])
  
      minx = min(minx, x)
      miny = min(miny, y)
      maxx = max(maxx, x)
      maxy = max(maxy, y)
  
  
  lx = minx
  rx = maxx
  
  while rx - lx > 10 ** (-7) and rx - lx > (rx / (10**6)):
  
      m1 = (lx * 2 + rx) / 3
      m2 = (lx + rx * 2) / 3
  
      rm1 = want2(m1)
      rm2 = want2(m2)
  
      if rm1 > rm2:
          lx = m1
      else:
          rx = m2
  
  print((rm1 + rm2) / 2)
  
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."}]