
_SCREAMING_SNAKE_CASE     :   str							 =      {
    '''0000''': '''0''',
    '''0001''': '''1''',
    '''0010''': '''2''',
    '''0011''': '''3''',
    '''0100''': '''4''',
    '''0101''': '''5''',
    '''0110''': '''6''',
    '''0111''': '''7''',
    '''1000''': '''8''',
    '''1001''': '''9''',
    '''1010''': '''a''',
    '''1011''': '''b''',
    '''1100''': '''c''',
    '''1101''': '''d''',
    '''1110''': '''e''',
    '''1111''': '''f''',
}

def 					SCREAMING_SNAKE_CASE  (   __UpperCamelCase			:    str							)			->							str:

				"""simple docstring"""







				A__	:						Optional[Any]								=				str(lowercase_							).strip()

				# Exceptions
				if not binary_str:
								raise ValueError('''Empty string was passed to the function'''							)
				A__	:						Optional[Any]								=				binary_str[0] == '''-'''
				A__	:						Optional[Any]								=				binary_str[1:] if is_negative else binary_str
				if not all(char in '''01''' for char in binary_str							):
								raise ValueError('''Non-binary value was passed to the function'''							)

				A__	:						Optional[int]								=				(
				    '''0''' * (4 * (divmod(len(lowercase_							)				,    4							)[0] + 1) - len(lowercase_							)) + binary_str
				)

				A__	:						Optional[int]								=				[]
				for x in range(0				,    len(lowercase_							)				,    4							):
								hexadecimal.append(BITS_TO_HEX[binary_str[x : x + 4]]							)
				A__	:						Union[str, Any]								=				'''0x''' + ''''''.join(lowercase_							)

				return "-" + hexadecimal_str if is_negative else hexadecimal_str


if __name__ == "__main__":
					from doctest import testmod

					testmod()
"""simple docstring"""







from collections import Counter



def       A__    (	lowercase_     :	list[int]						)  ->							int:
   return sum(socks_by_color // 2 for socks_by_color in Counter(lowercase_						).values()						)


if __name__ == "__main__":
     import doctest

     doctest.testmod()

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






