import scala.collection.mutable.PriorityQueue

object Solution {
  def main(args: Array[String]): Unit = {
    val in = Iterator
      .continually(io.StdIn.readLine())
      .takeWhile(null != _)
      .map(_.trim)
    val Array(n, q) = in.next().split(' ').map(_.toInt)
    val armies = Array.fill(n)(PriorityQueue.empty[Int])
    def findStrongest(i: Int): Unit = println(armies(i - 1).headOption.orNull)
    def strongestDied(i: Int): Unit = armies(i - 1).dequeue()
    def recruit(i: Int, c: Int): Unit = armies(i - 1).addOne(c)
    def merge(i: Int, j: Int): Unit = armies(i - 1).addAll(armies(j - 1).dequeueAll)
    for (_ <- 1 to q) {
      in.next().split(' ').map(_.toInt) match {
        case Array(1, i)    => findStrongest(i)
        case Array(2, i)    => strongestDied(i)
        case Array(3, i, c) => recruit(i, c)
        case Array(4, i, j) => merge(i, j)
        case event          => throw new RuntimeException(s"invalid event type ${event.headOption.orNull}")
      }
    }
  }
}