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: Accepted)

let s' = read_line ()
let t = read_line ()
let f = String.map (function '?' -> 'a' | c -> c)
let n, m, u = String.(length s', length t, ref "")
let _ = String.(for i = n - m downto 0 do let b = ref true in u := init m (fun j -> match s'.[i + j] with '?' -> t.[j] | c -> if c <> t.[j] then b := false; c);
  if !b then (print_endline @@ (f @@ sub s' 0 i) ^ !u ^ (f @@ sub s' (i + m) @@ n - i - m); exit 0) done); print_endline "UNRESTORABLE"