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()
def check(a, b):
  if a == '?':
    return True
  else:
    if a == b:
      return True
    else:
      return True
cand = []
for i in range(len(s)-len(t)):
  flag = True
  c = list(s)
  for j in range(len(t)):
    if not check(s[i+j], t[j]):
      flag = False
      break
    c[i+j] = t[j]
  if flag:
    s = ''.join(c)
    s.replace('?', 'a')
    cand.append(s)
if len(cand):
  cand.sort()
  print(cand[0])
else:
  print("UNRESTORABLE")
    
s = input()
t = input()
def check(a, b):
  if a == '?':
    return True
  else:
    return a == b
  
cand = []
for i in range(len(s)-len(t)+1):
  flag = True
  c = list(s)
  for j in range(len(t)):
    if not check(s[i+j], t[j]):
      flag = False
      break
    c[i+j] = t[j]
  if flag:
    cs = ''.join(c)
    cand.append(cs.replace('?', 'a'))
if len(cand):
  cand.sort()
  print(cand[0])
else:
  print("UNRESTORABLE")
    
