
import itertools

def 					SCREAMING_SNAKE_CASE  (   __UpperCamelCase			:    int = 1_00_00_00							)			->							int:

				"""simple docstring"""







				A__	:						Dict								=				[1]

				for i in itertools.count(len(lowercase_							)							):
								A__	:						Any								=				0
								for j in itertools.count(1							):
												A__	:						Optional[Any]								=				-1 if j % 2 == 0 else +1
												A__	:						Any								=				(j * j * 3 - j) // 2
												if index > i:
																break
												item += partitions[i - index] * sign
												item %= number
												index += j
												if index > i:
																break
												item += partitions[i - index] * sign
												item %= number

								if item == 0:
												return i
								partitions.append(lowercase_							)

				return 0


if __name__ == "__main__":
					import doctest

					doctest.testmod()

					print(f"""{solution() = }""")
"""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)}")






