import scala.math._

object Main {
  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt
    val xs = new Array[Int](11)
    for (i <- 0 to n-1) {
      val a, b, c = sc.nextInt
      xs(a) += 1
      xs(b) += 1
      xs(c) += 1
    }

    val div = (1 to 10).map { e => xs(e) / 2 }.sum
    val mod = (1 to 10).map { e => xs(e) % 2 }.sum
    val ans = div + (mod / 4)
    println(ans)
  }
}