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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

func main() {
	var s, t string
	fmt.Scan(&s, &t)
	s = reverse(s)
	t = reverse(t)

	for i := 0; i < len(s); i++ {
		ok := true
		for j := 0; j < len(t); j++ {
			if len(s) <= i+j {
				ok = false
				break
			}
			tt := t[j]
			ss := s[i+j]
			if !(ss == tt || ss == '?') {
				ok = false
				break
			}
		}
		if ok {
			ans := ""
			for j := 0; j < len(s); j++ {
				c := s[j]
				if i <= j && j < i+len(t) {
					c = t[j-i]
				} else if c == '?' {
					c = 'a'
				}
				ans += string(c)
			}
			fmt.Println(reverse(ans))
			return
		}
	}
	fmt.Println("UNRESTORABLE")
}

func reverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}
	return string(runes)
}