import java.util.*
import kotlin.math.abs

fun main(args: Array<String>) {
    val treeSet: TreeSet<Int> = TreeSet()
    val scanner = Scanner(System.`in`)
    val inpSize = scanner.nextInt()
    for (i in 0 until inpSize) {
        when (scanner.next()) {
            "+1" -> treeSet.add(scanner.nextInt())
            "-1" -> treeSet.remove(scanner.nextInt())
            "0" -> {
                var inp = scanner.nextInt()
                println(nth(treeSet, abs(inp), if (inp > 0) ::higherZero else ::lowerZero))
            }
        }
    }
}

fun nth(treeSet: TreeSet<Int>, n: Int, function: (TreeSet<Int>) -> Int): Int {
    val list: LinkedList<Int> = LinkedList()
    for (i in 1 until n) {
        list.add(function(treeSet))
        treeSet.remove(list.last)
    }
    val max = treeSet.floor(Int.MAX_VALUE)!!
    treeSet.addAll(list)
    return max
}

fun lowerZero(treeSet: TreeSet<Int>): Int{
    return treeSet.ceiling(Int.MIN_VALUE)!!
}

fun higherZero(treeSet: TreeSet<Int>): Int{
    return treeSet.floor(Int.MAX_VALUE)!!
}