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 OCaml (4.02.3) (judge verdict: Wrong Answer)

let q2a s = String.map (fun c -> if c = '?' then 'a' else c) s

let f s' t =
  let lens = String.length s' in
  let lent = String.length t in
  let rec inner si ti =
    if ti >= lent then true
    else
      match (s'.[si], t.[ti]) with
      | a, b when a = b -> inner (si + 1) (ti + 1)
      | '?', _ -> inner (si + 1) (ti + 1)
      | _, _ -> false
  in
  let rec outer si =
    if si > lens - lent then "UNRESTORABLE"
    else if inner si 0
    then String.sub s' 0 si ^ t ^ String.sub s' (si + lent) (lens - si - lent)
    else outer (si + 1)
  in
  outer 0


let () = Scanf.scanf "%s\n%s" f |> q2a |> print_endline