import math._
import scala.collection.mutable.HashMap

object Main {
  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt
    val d = new HashMap[Int, Int]
    for (i <- 1 to n) {
      val x = sc.nextInt
      if (!d.contains(x)) d(x) = 0
      d(x) += 1
    }

    println(d.values count { e => e == 1 })
  }
}