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)

module SSet = Set.Make(String);;
Scanf.(Array.(scanf" %s %s"@@fun s t->
	let open Printf in
	let k,l = String.length s,String.length t in
	print_endline@@
		if k<l then "UNRESTORABLE"
		else try
			let st = ref SSet.empty in
			for i=0 to k-l do
				(* printf "[%d %d]\n" i (i+l-1); *)
				let f = ref true in
				for j=i to i+l-1 do
					(* printf "  %c  %c\n" s.[j] t.[j-i]; *)
					if s.[j]='?' || s.[j]=t.[j-i] then () else f:=false;
				done;
				if !f then st := SSet.add (
					init k (fun j ->
						if i<=j && j<=i+l-1 then t.[j-i]
						else if s.[j] = '?' then 'a'
						else s.[j]
					) |> map (String.make 1) |> Array.to_list |> String.concat ""
				) !st;
			done;
			!st |> SSet.min_elt
		with Not_found -> "UNRESTORABLE"
))