import java.util.Scanner

trait Reader {
  val scanner = new Scanner(System.in)
}

object Main extends App with Reader {

  val a = scanner.nextInt()
  val b = scanner.nextInt()
  val c = scanner.nextInt()

  val answer = Seq(a, b, c).foldLeft(Map[Int, Int]()) { (acc, element) =>
    acc.updated(element, acc.getOrElse(element, 0) + 1)
  }.minBy(_._2)._1

  println(answer)
}