output_description: Print the maximum satisfaction that you can obtain.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      t_1 d_1
      t_2 d_2
      .
      .
      .
      t_N d_N
attempt: n, k = map(int, input().split())
  inputarray = []
  for i in range(n):
      inputarray.append([int(i) for i in input().split()])
  t = [i[0] for i in inputarray]
  d = [i[1] for i in inputarray]
  
  
  def combinationListRecursive(data, r):
      if r == 0 or r > len(data):
          return []
  
      result = []
      _combinationListRecursive(data, r, 0, [], result)
      return result
  
  
  def _combinationListRecursive(data, r, start, progress, result):
      if r == 0:
          result.append(progress)
          return
  
      for i in range(start, len(data)):
          _combinationListRecursive(data, r - 1, i + 1, progress + [data[i]], result)
  
  
  result = combinationListRecursive(range(len(d)), k)
  best = 0
  for i in result:
      tarray = []
      dtmp = 0
      for k in range(k):
          dtmp += d[i[k]]
          tarray.append(t[i[k]])
      tlist = list(set(tarray))
      ttmp = len(tlist) ** 2
      if best < dtmp + ttmp:
          best = dtmp + ttmp
  print(best)
  
problem_description: Statement
  
  There are N pieces of sushi. Each piece has two parameters: "kind of topping"
  t_i and "deliciousness" d_i. You are choosing K among these N pieces to eat.
  Your "satisfaction" here will be calculated as follows:
  
    * The satisfaction is the sum of the "base total deliciousness" and the "variety bonus".
    * The base total deliciousness is the sum of the deliciousness of the pieces you eat.
    * The variety bonus is x*x, where x is the number of different kinds of toppings of the pieces you eat.
  
  You want to have as much satisfaction as possible. Find this maximum
  satisfaction.
samples: [{"input": "5 3\n    1 9\n    1 7\n    2 6\n    2 5\n    3 1", "output": "26\n    \n\nIf you eat Sushi 1,2 and 3:\n\n  * The base total deliciousness is 9+7+6=22.\n  * The variety bonus is 2*2=4.\n\nThus, your satisfaction will be 26, which is optimal.\n\n* * *"}, {"input": "7 4\n    1 1\n    2 1\n    3 1\n    4 6\n    4 5\n    4 5\n    4 5", "output": "25\n    \n\nIt is optimal to eat Sushi 1,2,3 and 4.\n\n* * *"}, {"input": "6 5\n    5 1000000000\n    2 990000000\n    3 980000000\n    6 970000000\n    6 960000000\n    4 950000000", "output": "4900000016\n    \n\nNote that the output may not fit into a 32-bit integer type."}]