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`.
s = input()
t = input()
left = 0

insert_index = -1
while True:

    flag = True

    if left + len(t) - 1 == len(s):
        break
    print(s[left:left+len(t)], t)

    for a, b in zip(s[left:left+len(t)], t):
        if a != b and a != "?":
            flag = False
            break

    left += 1

    if flag:
        insert_index = max(insert_index, left)

if insert_index == -1:
    print("UNRESTORABLE")
else:
    next_word = s[:insert_index] + t + s[len(t)+insert_index:]
    ans = next_word.replace("?", "a")
    print(ans)

s = input()
t = input()
left = 0

insert_index = -1
while True:

    flag = True

    if left + len(t) - 1 == len(s):
        break

    for a, b in zip(s[left:left+len(t)], t):
        if a != b and a != "?":
            flag = False
            break
    if flag:
        insert_index = max(insert_index, left)
    left += 1


if insert_index == -1:
    print("UNRESTORABLE")
else:
    next_word = s[:insert_index] + t + s[insert_index+len(t):]

    ans = next_word.replace("?", "a")
    print(ans)
