题解 | #密码截取#

while True:
    try:

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