import kotlin.system.exitProcess

val br = System.`in`.bufferedReader()

fun readLine(): String? = br.readLine()
fun readString() = readLine()!!
fun readInt() = readString().toInt()
fun readStrings() = readLine()?.split(" ")?.filter { it.isNotEmpty() } ?: listOf()

const val MAX_STACK_SIZE: Long = 128 * 1024 * 1024

fun main() {
    val thread = Thread(null, ::run, "solve", MAX_STACK_SIZE)
    thread.setUncaughtExceptionHandler { _, e -> e.printStackTrace(); exitProcess(1) }
    thread.start()
}

fun run() {
    val N = readInt()
    val pairs = Array(N) { readStrings() }
    output(solve(pairs))
}

fun solve(pairs: Array<List<String>>): List<String> {
    val cheaters = pairs.map { it.first() }.toHashSet()
    val used = HashSet<String>()
    val res = mutableListOf<String>()
    pairs.map { it[1] }.forEach {
        if (it !in cheaters && !used.contains(it)) {
            res.add(it)
            used.add(it)
        }
    }
    return res
}

fun output(res: List<String>) =
    res.joinToString("\n")
        .apply { println(this) }