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: Wrong Answer)

package main

import "fmt"

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

	ans := make([]rune, len(s))
	j := 0
	for i := range s {
		if j == len(t) {
			if s[i] == '?' {
				ans[i] = 'a'
			} else {
				ans[i] = rune(s[i])
			}

			continue
		}

		if s[i] == '?' {
			ans[i] = 'a'
		} else if s[i] == t[j] {
			ans[i] = rune(s[i])
		} else {
			ans[i] = rune(s[i])
			if s[i] == t[0] {
				j = 1
			} else {
				j = 0
			}

			continue
		}

		j++
		if j == len(t) {
			for k := 0; k < j; k++ {
				ans[i-j+1+k] = rune(t[k])
			}
		}
	}

	if j == len(t) {
		fmt.Println(string(ans))
	} else {
		fmt.Println("UNRESTORABLE")
	}
}