import java.util.Scanner

object Problem182 {
  def main(args: Array[String]) {
    val sc = new Scanner(System.in)
    val N = sc.nextInt()
    val A = List.fill(N)(sc.nextInt())

    val m = collection.mutable.Set[Int]()
    val duplicate = collection.mutable.Set[Int]()
    A foreach { x =>
      if (m.contains(x)) {
        duplicate.add(x)
      } else {
        m.add(x)
      }
    }

    val result = (m -- duplicate).size
    println(result)
  }
}