import scala.collection.mutable.ArrayBuffer
import scala.io.StdIn

object Main extends App {

  var ss = StdIn.readLine()
  val t = StdIn.readLine()
  val buff = ArrayBuffer.empty[Char]
  val ret = ArrayBuffer.empty[String]

  val len = ss.length
  val lent = t.length
  var i = 0
  while (i < len) {
    var j = 0
    var k = i
    var unmatch = false
    buff.clear()
    while (j < lent && !unmatch && k < len) {
      if(t(j) == ss(k) || ss(k) == '?'){
        buff.append(t(j))
        j += 1
        k += 1
      } else {
        unmatch = true
      }
    }
    if(j == lent && !unmatch){
      ret.append(buff.mkString(""))
      ret.append(ss.drop(k))
      i += len
    } else {
      ret.append(ss(i).toString)
      i += 1
    }
  }

  val result = ret.mkString("")
  println(if(len < lent || result == ss) "UNRESTORABLE" else result.replace("?", "a"))

}