题解 | 最长回文子串

s = input()
n = len(s)
max_len = 0
for i in range(n-1):
    for j in range(i+1,n+1):
        sub = s[i:j]
        if sub == sub[::-1] and j - i >max_len:
            max_len = j - i
print(max_len)