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()
t = len(T)

for i in range(len(S)-t, -1, -1):
    print(i)
    for j in range(t):
        k = S[i+j]
        if k != T[j] and k != "?":
            break
    else:
        print((S[:i]+T+S[i+t:]).replace("?", "a"))
        exit()
print("UNRESTORABLE")
S = input()
T = input()
t = len(T)

for i in range(len(S)-t, -1, -1):
    for j in range(t):
        k = S[i+j]
        if k != T[j] and k != "?":
            break
    else:
        print((S[:i]+T+S[i+t:]).replace("?", "a"))
        exit()
print("UNRESTORABLE")