object Main extends App {
  val sc = new java.util.Scanner(System.in)
  val s, t = sc.next()
  if (s.length < t.length) {
    println("UNRESTORABLE")
  } else {
    s.toSeq.sliding(t.length).zipWithIndex.toList.reverse.find(
      _._1.zip(t).forall{case (c1, c2) => c1 == '?' || c1 == c2}
    ) match {
      case Some((_, idx)) =>
        println(s"${s.take(idx).replace('?', 'a')}$t${s.drop(idx + t.length).replace('?', 'a')}")
      case None => println("UNRESTORABLE")
    }
  }
}
