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 (4.10.0) (judge verdict: Accepted)

Scanf.scanf "%s %s" (fun s t ->
    let n = String.length s in
    let tn = String.length t in

    let check p =
        let rec loop j =
            if j = tn then true else
                if s.[p + j] = t.[j] || s.[p + j] = '?' then loop (j + 1) else false
        in
        loop 0
    in

    let make p =
        String.init n (fun i ->
            if s.[i] <> '?' then s.[i] else
                if i < p || i >= p + tn then 'a' else t.[i - p]
        )
    in

    let rec loop i acc =
        if i < 0 then acc else
            let acc = if check i then min acc (make i) else acc in
            loop (i - 1) acc
    in
    let r = loop (n - tn) "{" in
    print_endline @@ if r = "{" then "UNRESTORABLE" else r
)