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: num_lines, max_num = map(int, input().split())
  
  inp_sorted = [[int(st) for st in input().split()] for _ in range(num_lines)]
  # print(inp_sorted)
  inp_sorted.sort(key=lambda x: x[1], reverse=True)
  
  inp_map = {}
  for t, d in inp_sorted:
      if not t in inp_map:
          inp_map[t] = d
  
  variety = set()
  score = 0
  
  dup = []
  for i in range(max_num):
      t, d = inp_sorted[i]
      if t in variety:
          dup.append((t, d))
      variety.add(t)
      if t in inp_map:
          del inp_map[t]
      score += d
  
  var_value = len(variety)
  max_score = score + var_value * var_value
  
  for t, d in sorted(inp_map.items(), key=lambda x: x[1], reverse=True):
      if len(dup):
          t2, d2 = dup.pop()
          var_value += 1
          score = score - d2 + d
          max_score = max(max_score, score + var_value * var_value)
  
  print(max_score)
  
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."}]