题解 | #密码截取#

while True:
    try:
        s = input()
        p = 0
        for i in range(len(s)):
            for j in range(i,len(s)):
                if s[i] == s[j] and s[i+1:j] == s[i+1:j][::-1] and j + 1 - i > p:
                    p = j + 1 - i
        print(p)

    except:
        break