object Solution {
    
    def solve(n: Int, input: Seq[Int]): Unit = {
      implicit val orderingIntSeq: Ordering[Seq[Int]] = (lsa: Seq[Int], lsb: Seq[Int]) =>
        implicitly[Ordering[Int]].compare(lsa.head, lsb.head)

      println(
        input.grouped(2).toList.groupBy(_.head)
          .filter(_._2.length == n)
          .view.mapValues(_.minBy(_.tail)).toMap
          .values
          .toList
          .sortBy(_.head)
          .map(_.mkString(" "))
          .reduce(_ + " " + _)
      )
    }
    
    def apply(): Unit = {
      val N: Int = io.StdIn.readLine().trim.toInt

      val inputList: Seq[Int] = (1 to N).flatMap { _ =>
        val input: Array[Int] =
          io.StdIn.readLine().trim.split(" ").map(_.toInt)

        input
      }

      solve(N, inputList)
    }
    
    def main(args: Array[String]) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution
*/      Solution.apply()
    }
}