output_description: Print the maximum number of pairs that can be created.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N M
      X_1 X_2 ... X_N
attempt: import sys
  
  
  def count_of_num(list, num):
      count = 0
      for item in list:
          if item == num:
              count += 1
      return count
  
  
  N, M = map(int, input().split())
  nums = [n for n in map(int, input().split())]
  
  pairs = 0
  rest = nums
  bFound = True
  while bFound:
      bFound = False
      for i in range(len(rest)):
          for j in range(i + 1, len(rest)):
              num1 = rest[i]
              num2 = rest[j]
              if (rest[i] + rest[j]) % M == 0:
                  if (count_of_num(rest, rest[i]) % 2 == 1) or (
                      count_of_num(rest, rest[j]) % 2 == 1
                  ):
                      pairs += 1
                      rest.remove(num1)
                      rest.remove(num2)
                      bFound = True
                      break
          if bFound:
              break
  bFound = True
  while bFound:
      bFound = False
      for i in range(len(rest)):
          for j in range(i + 1, len(rest)):
              if rest[i] == rest[j]:
                  num = rest[i]
                  rest.remove(num)
                  rest.remove(num)
                  pairs += 1
                  bFound = True
                  break
          if bFound:
              break
  
  print(pairs)
  
problem_description: Statement
  
  Takahashi is playing with N cards.
  
  The i-th card has an integer X_i on it.
  
  Takahashi is trying to create as many pairs of cards as possible satisfying
  one of the following conditions:
  
    * The integers on the two cards are the same.
    * The sum of the integers on the two cards is a multiple of M.
  
  Find the maximum number of pairs that can be created.
  
  Note that a card cannot be used in more than one pair.
samples: [{"input": "7 5\n    3 1 4 1 5 9 2", "output": "3\n    \n\nThree pairs (3,2), (1,4) and (1,9) can be created.\n\nIt is possible to create pairs (3,2) and (1,1), but the number of pairs is not\nmaximized with this.\n\n* * *"}, {"input": "15 10\n    1 5 6 10 11 11 11 20 21 25 25 26 99 99 99", "output": "6"}]