output_description: Print coordinates of the tangent points on the circle $c$ based on the
  following rules.
  
    * Print the coordinate with smaller $x$ first. In case of a tie, print the coordinate with smaller $y$ first.
  
  The output values should be in a decimal fraction with an error less than
  0.00001.
input_description: The input is given in the following format.
  
  $px \; py$  
  $cx \; cy \; r$
  
  $px$ and $py$ represents the coordinate of the point $p$. $cx$, $cy$ and $r$
  represents the center coordinate and radius of the circle $c$ respectively.
  All input values are given in integers.
attempt: px, py = map(int, input().split())
  cx, cy, r = map(int, input().split())
  dx, dy = px - cx, py - cy
  s2 = dx**2 + dy**2
  df = (s2 - r**2) ** 0.5
  ix1, ix2 = (dx * r + dy * df) / s2, (dx * r - dy * df) / s2
  iy1, iy2 = (dy * r - dx * df) / s2, (dy * r + dx * df) / s2
  if (ix1, iy1) > (ix2, iy2):
      ix1, ix2 = ix2, ix1
      iy1, iy2 = iy2, iy1
  print(ix1 + cx, iy1 + cy)
  print(ix2 + cx, iy2 + cy)
  
problem_description: Tangent to a Circle
  
  Find the tangent lines between a point $p$ and a circle $c$.
samples: [{"input": "0 0\n    2 2 2", "output": "0.0000000000 2.0000000000\n    2.0000000000 0.0000000000"}, {"input": "-3 0\n    2 2 2", "output": "0.6206896552 3.4482758621\n    2.0000000000 0.0000000000"}]