题解 | #密码截取#

def expand(s, i, j):
    while i >= 0 and j < len(s) and s[i] == s[j]:
        i -= 1
        j += 1
    return i + 1, j - 1
while True:
    try:
        s = input()
        max_lens = 0
        for i in range(len(s)):
            l1, r1 = expand(s, i, i)
            l2, r2 = expand(s, i, i+1)
            if r1 - l1 + 1 > max_lens:
                max_lens = r1 - l1 + 1
            if r2 - l2 + 1 > max_lens:
                max_lens = r2 - l2 + 1
        print(max_lens)
    except:
        break