output_description: Print the answer.
  
  It will be considered correct if its 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 K
      x_1 y_1 c_1
      \vdots
      x_N y_N c_N
attempt: import math
  
  N, K = map(int, input().split())
  xyc_array = [list(map(float, input().split())) for _ in range(N)]
  # print(xyc_array)
  ans = 100000
  for i in range(N):
      for j in range(i + 1, N):
          x_i, y_i, c_i = xyc_array[i]
          x_j, y_j, c_j = xyc_array[j]
          gx = (c_i * x_i + c_j * x_j) / (c_i + c_j)
          gy = (c_i * y_i + c_j * y_j) / (c_i + c_j)
          time_array = [
              c * math.sqrt((x - gx) ** 2 + (y - gy) ** 2) for x, y, c in xyc_array
          ]
          time_array.sort()
          ans = min(ans, time_array[K - 1])
          if c_i != c_j:
              gx = (-c_i * x_i + c_j * x_j) / (c_i - c_j)
              gy = (-c_i * y_i + c_j * y_j) / (c_i - c_j)
              # print(gx,gy)
              time_array = [
                  c * math.sqrt((x - gx) ** 2 + (y - gy) ** 2) for x, y, c in xyc_array
              ]
              time_array.sort()
              ans = min(ans, time_array[K - 1])
  print(ans)
  
problem_description: Statement
  
  Takahashi wants to grill N pieces of meat on a grilling net, which can be seen
  as a two-dimensional plane. The coordinates of the i-th piece of meat are
  \left(x_i, y_i\right), and its _hardness_ is c_i.
  
  Takahashi can use one heat source to grill the meat. If he puts the heat
  source at coordinates \left(X, Y\right), where X and Y are real numbers, the
  i-th piece of meat will be ready to eat in c_i \times \sqrt{\left(X -
  x_i\right)^2 + \left(Y-y_i\right)^2} seconds.
  
  Takahashi wants to eat K pieces of meat. Find the time required to have K or
  more pieces of meat ready if he put the heat source to minimize this time.
samples: [{"input": "4 3\n    -1 0 3\n    0 0 3\n    1 0 2\n    1 1 40", "output": "2.4\n    \n\nIf we put the heat source at \\left(-0.2, 0\\right), the 1-st, 2-nd, and 3-rd\npieces of meat will be ready to eat within 2.4 seconds. This is the optimal\nplace to put the heat source.\n\n* * *"}, {"input": "10 5\n    -879 981 26\n    890 -406 81\n    512 859 97\n    362 -955 25\n    128 553 17\n    -885 763 2\n    449 310 57\n    -656 -204 11\n    -270 76 40\n    184 170 16", "output": "7411.2252"}]