import java.io.BufferedInputStream

fun main(args: Array<String>){
    fun iterateTokens(): Iterator<String> {
        val reader = BufferedInputStream(System.`in`).bufferedReader()
        val iterator = reader.lineSequence()
                .map { it.split(" ") }
                .reduce { left, right -> left + right }
                .iterator()
        return iterator
    }
    val tokens = iterateTokens()
    val n = tokens.next().toInt()
    val aList = LongArray(n)
    for (i in 0 until n){
        aList[i] = tokens.next().toLong()
    }
    val map = mutableMapOf<Long, Int>().withDefault{ 0 }
    for (a in aList){
        map[a] = (map[a]?:0) + 1
    }
    println(map.filter{ it.value == 1}.size)
}