fun main(args: Array<String>) {
	val N = readLine()!!.toInt()
	val dic = Array(10) { 0 }
	var cnt = 0

	for (i in 0 until N) {
		val abc = readLine()!!.split(" ").map { it.toInt() }
		for (v in abc) {
			dic[v - 1] += 1
		}
	}

	for (i in 0 until dic.size) {
		while (dic[i] >= 2) {
			dic[i] -= 2
			cnt += 1
		}
	}

	cnt += dic.sum() / 4
	println(cnt)
}