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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Data.Bool
import Data.Maybe
import Data.List

main = putStrLn . solve . lines =<< getContents

solve :: [String] -> String
solve [s,t] = maybe "UNRESTORABLE" (rpl s t) $ rfnd s t (length s - length t)

rpl s t i = f ++ t ++ b
    where
        f = map rpl' $ take i s
        b = map rpl' $ drop (length t + i) s

rpl' '?' = 'a'
rpl' x = x

rfnd s t i
    | i < 0 = Nothing
    | otherwise = bool (rfnd s t (i-1)) (return i) $ isMatched s' t
    where
        s' = drop i s

isMatched s t = and $ zipWith (\s' t' -> s' == '?' || s' == t') s t