题解 | #密码截取#

def find(string):
    res = ''
    for i in range(len(string)):
        start = max(i - len(res) -1, 0)
        temp = string[start: i+1]
        if temp == temp[::-1]:
            res = temp
        else:
            temp = temp[1:]
            if temp == temp[::-1]:
                res = temp
    return len(res)
    
string = input().strip()
print(find(string))