






"""simple docstring"""



from collections import Counter
def 		_SCREAMING_SNAKE_CASE					(       __snake_case     :    list[int]       ):





  '''simple docstring'''





  return sum(socks_by_color // 2 for socks_by_color in Counter(__snake_case       ).values()       )


if __name__ == "__main__":
    import doctest

    doctest.testmod()

    _UpperCamelCase						:    str		=						[int(x) for x in input('Enter socks by color :').rstrip().split()]
    print(F'''sock_merchant({colors}) = {sock_merchant(colors)}''')






import os







def 	A (		):
     UpperCAmelCase    :					Any			=      os.path.dirname(os.path.realpath(A__			)			)
     UpperCAmelCase    :					Optional[int]			=      os.path.join(A__		,		"triangle.txt"			)

     with open(A__			) as f:
          UpperCAmelCase    :					Union[str, Any]			=      f.readlines()

     UpperCAmelCase    :					List[str]			=      [[int(A__			) for y in x.rstrip("\r\n"			).split(" "			)] for x in triangle]

     for i in range(1		,		len(A__			)			):
          for j in range(len(a[i]			)			):
               UpperCAmelCase    :					List[Any]			=      a[i - 1][j] if j != len(a[i - 1]			) else 0
               UpperCAmelCase    :					Optional[int]			=      a[i - 1][j - 1] if j > 0 else 0
               a[i][j] += max(A__		,		A__			)
     return max(a[-1]			)


if __name__ == "__main__":
      print(solution())



