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`.
import bisect
import numpy as np
import sys
input = sys.stdin.readline
def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

s = S()
t = S()

f = 0
for i in range(len(s)-len(t)+1):
	cnt = 0
	for j in range(i,i+len(t)-1):
		if s[j] == t[j-i] or s[j] == "?":
			cnt += 1
			continue
		else:
			break
	if cnt == len(t)-1:
		A = i
		f = 1
		break

if f == 0:
	print("UNRESTORABLE")
else:
	print(s.translate(str.maketrans({'?':'a'}))[:A]+t+s[A+len(t):])
import bisect
import numpy as np
import sys

def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

s = S()
t = S()

f = 0
for i in range(len(s)-len(t),-1,-1):
    for j in range(len(t)):
        if s[i+j] == t[j] or s[i+j] == "?":
            continue
        else:
            break
    else:
        a = s[:i]+t+s[i+len(t):]
        print(a.replace('?', 'a'))
        break
else:
    print("UNRESTORABLE")