s = input()
n = len(s)
maxlist = ["a"]
listlen = 1
lastplusind = n
ans = [s[i] for i in range(n)]
for i in reversed(range(n)):
    if ans[i] == "?":
        ans[i] = maxlist[-1]
    else:
        left = -1
        right = listlen
        while right - left >= 2:
            mid = (right + left) // 2
            if ans[i] < maxlist[mid]:
                left = mid
            else:
                right = mid
        if right == listlen:
            lastplusind = i
            maxlist.append(ans[i])
            listlen += 1
        else:
            maxlist[right] = ans[i]

for i in range(lastplusind,n):
    if s[i] == "?":
        ans[i] = "a"

ans=''.join(ans)
print(ans)