output_description: Print the expected x\- and y-coordinates of the center of the circle inscribed
  in the triangle formed by the chosen points. Your output will be considered
  correct when the absolute or relative error is at most 10^{-9}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N L
      T_1
      :
      T_N
attempt: from math import pi, cos, sin
  from itertools import combinations
  
  
  def centerP(a, b, c):
      da = dist(b, c)
      db = dist(c, a)
      dc = dist(a, b)
      dt = da + db + dc
      return (da * a[0] + db * b[0] + dc * c[0]) / dt, (
          da * a[1] + db * b[1] + dc * c[1]
      ) / dt
  
  
  def dist(a, b):
      return ((a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2) ** 0.5
  
  
  N, L = map(int, input().split())
  P = []
  for i in range(N):
      T = int(input())
      P.append([cos(2 * pi * T / L), sin(2 * pi * T / L)])
  
  sumx = 0
  sumy = 0
  li = combinations(P, 3)
  
  for a, b, c in li:
      x, y = centerP(a, b, c)
      sumx += x
      sumy += y
  
  print(sumx / N, sumy / N)
  
problem_description: Statement
  
  Given are N points on the circumference of a circle centered at (0,0) in an
  xy-plane. The coordinates of the i-th point are (\cos(\frac{2\pi
  T_i}{L}),\sin(\frac{2\pi T_i}{L})).
  
  Three distinct points will be chosen uniformly at random from these N points.
  Find the expected x\- and y-coordinates of the center of the circle inscribed
  in the triangle formed by the chosen points.
samples: [{"input": "3 4\n    0\n    1\n    3", "output": "0.414213562373095 -0.000000000000000\n    \n\nThe three points have the coordinates (1,0), (0,1), and (0,-1). The center of\nthe circle inscribed in the triangle formed by these points is (\\sqrt{2}-1,0).\n\n* * *"}, {"input": "4 8\n    1\n    3\n    5\n    6", "output": "-0.229401949926902 -0.153281482438188\n    \n\n* * *"}, {"input": "10 100\n    2\n    11\n    35\n    42\n    54\n    69\n    89\n    91\n    93\n    99", "output": "0.352886583546338 -0.109065017701873"}]