题解 | #最长回文子串#

def check(x): #确认是否对称
    l = int(len(x)/2)
    if x[:l] == x[l:][::-1] and len(x)%2==0:
        return True
    elif x[:l] == x[(l+1):][::-1] and len(x)%2==1:
        return True
    else:
        return False

def cal(x): #计算最大子串长度
    result = ''
    for i in range(len(x)+1):
        for j in range(0,len(x)-i+1):
            if check(x[j:(j+i)]) and len(x[j:(j+i)]) > len(result):
                result = x[j:(j+i)]
    return result

while True:
    try:
        x = input()
        print(len(cal(x)))
    except:
        break