题解 | #密码截取#

while True:
    try:
        s=input()
        l=[]
        for i in range(len(s)-1):
            for j in range(1,len(s)):
                if s[i]==s[j] and s[i+1:j]==s[j-1:i:-1]:
                    l.append(len(s[i:j+1]))
        print(max(l))
    except:
        break