import Data.List
main = do
 ss<-getLine
 t<-getLine
 let ls = length ss
 let lt = length t
 let candi = [f ss t k| k<-[0..ls-lt]]
 let candi2 = filter (g ss) candi
 putStrLn $ if null candi2 then "UNRESTORABLE" else head $ sort $ map h candi2
 
f x y k = (take k x) ++ y ++ (drop (k + length y) x)
g [] [] = True
g (x:xs) (y:ys) = ((x == y) or (x == '?')) and g xs ys
h [] = []
h (x:xs)
    |x=='?' = 'a':(h xs)
    |otherwise = x:(h xs)