func main()
	var items: []int :: #[11]int
	var n: int :: cui@inputInt()
	for(1, n)
		for(1, 3)
			do items[cui@inputInt()] :+ 1
		end for
	end for
	
	var remains: int
	var ans: int
	for i(1, 10)
		do ans :+ items[i] / 2
		do remains :+ items[i] % 2
	end for
	do ans :+ remains / 4
	do cui@print("\{ans}\n")
end func