import java.util.Scanner

object A {
  def kadomatsu(n1 :Int, n2: Int, n3: Int): Boolean = {
    if(n1 < n2 && n2 > n3) {
      return true
    }
    if(n1 > n2 && n2 < n3) {
      return true
    }
    return false
  }
  def main(args: Array[String]): Unit = {
    val sc = new Scanner(System.in)
    val c1, c2, c3 = sc.next()
    if(c1=="?") {
      val n2 = c2.toInt
      val n3 = c3.toInt
      if(kadomatsu(1, n2, n3)) {
        print(1)
      }
      if(kadomatsu(4, n2, n3)) {
        print(4)
      }
    } else if(c2=="?") {
      val n1 = c1.toInt
      val n3 = c3.toInt
      if(kadomatsu(n1, 1, n3)) {
        print(1)
      }
      if(kadomatsu(n1, 4, n3)) {
        print(4)
      }
    } else {
      val n1 = c1.toInt
      val n2 = c2.toInt
      if(kadomatsu(n1, n2, 1)) {
        print(1)
      }
      if(kadomatsu(n1, n2, 4)) {
        print(4)
      }
    }
    println()
  }
}