object main{
  object Solver extends InputReader{
    def solve(){
      val n = getInt()
      val a = new Array[Int](10)
      for(_ <- 1 to (n * 3))
        a(getInt() - 1) += 1
      val s = a.map(_ / 2).sum
      val d = a.map(_ % 2).sum / 4
      println(s + d)
    }
  }

  // TEMPLATE ------------------------

  def main(args: Array[String]){
    Solver.solve()
  }

  trait InputReader{
    import java.io._
    import java.util._
    protected val stream = System.in
    private val reader = new BufferedReader(new InputStreamReader(stream))
    private var tokenizer = new StringTokenizer(reader.readLine())

    def getStr(): String = {
      while(!tokenizer.hasMoreTokens())
        tokenizer = new StringTokenizer(reader.readLine())
      tokenizer.nextToken()
    }

    def getInt(): Int = getStr().toInt
    def getLong(): Long = getStr().toLong
    def getDouble(): Double = getStr().toDouble
  }
}