题解 | #最长回文子串#

while True:
    try:
        s = input()
        res = ''
        for i in range(len(s)):
            start = max(0, i - len(res) - 1)
            tmp = s[start: i+1]
            if tmp == tmp[::-1]:
                res = tmp
            else:
                tmp = tmp[1:]
                if tmp == tmp[::-1]:
                    res = tmp
        print(len(res))
    except:
        break