# palindroms

word = input()
length = len(word)
mid = ""
word1 = list(word[:length // 2])
if length % 2:
    word2 = list(word[length // 2 + 1:][::-1])
    mid = word[length // 2]
    if mid == "?":
        mid = "0"
else:
    word2 = list(word[length // 2:][::-1])


for index in range(length // 2):
    if word1[index] == "?":
        if word2[index] == "?":
            word1[index], word2[index] = "0", "0"
        else:
            word1[index] = word2[index]
    else:
        if word2[index] == "?":
            word2[index] = word1[index]

if word1 != word2:
    print("NO SOLUTION")
else:
    print("".join(word1) + mid + "".join(word2))