题解 | #最长回文子串#

import sys

def do(sentence):
    result = []
    for i in range(len(sentence)):
        for j in range(len(sentence), i, -1):
            # print('{}{}{}'.format(i,j,sentence[i:j]))
            tem = sentence[i:j]
            if tem == tem[::-1]:
                result.append(len(tem)) 
    return max(result)


if __name__ == '__main__':
    str = sys.stdin.readline().strip()
    r = do(str)
    print(r)