Problem:
Score : 300 points

Problem Statement

E869120 found a chest which is likely to contain treasure.

However, the chest is locked. In order to open it, he needs to enter a string S consisting of lowercase English letters.

He also found a string S', which turns out to be the string S with some of its letters (possibly all or none) replaced with ?.

One more thing he found is a sheet of paper with the following facts written on it:

Condition 1: The string S contains a string T as a contiguous substring.

Condition 2: S is the lexicographically smallest string among the ones that satisfy Condition 1.

Print the string S.

If such a string does not exist, print UNRESTORABLE.

Constraints

1 \leq |S'|, |T| \leq 50

S' consists of lowercase English letters and ?.

T consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S
T'

Output

Print the string S.

If such a string does not exist, print UNRESTORABLE instead.

Sample Input 1

?tc????
coder

Sample Output 1

atcoder

There are 26 strings that satisfy Condition 1: atcoder, btcoder, ctcoder,..., ztcoder.
Among them, the lexicographically smallest is atcoder, so we can say S = atcoder.

Sample Input 2

??p??d??
abc

Sample Output 2

UNRESTORABLE

There is no string that satisfies Condition 1, so the string S does not exist.

Solution in Scala (2.11.7) (judge verdict: Wrong Answer)

import scala.io.StdIn

object Main extends App {

  var ss = StdIn.readLine()
  val t = StdIn.readLine()
  var replaced = false

  def solve(i: Int): String = {
    if (i == 0) {
      ss
    } else {
      var k = 0
      while (k < t.length && 0 <= i - k && (ss(i - k) == t(t.length - k - 1) || ss(i - k) == '?')) {
        k += 1
      }
      if (k == t.length) {
        replaced = true
        val idx = i + 1 - k
        ss.take(idx) + t + ss.drop(idx + k)
      } else {
        solve(i - 1)
      }
    }
  }

  val r = solve(ss.length - 1)
  println(if (!replaced) "UNRESTORABLE" else r.replace("?", "a"))

}