题解 | #最长回文子串#

'''
a='gsdgdaber'
print(len(a),a[4:7])
for i in range(len(a)):
    for j in range(i+1,len(a)):
        print(type(i),type(j))
        string_cut=a[i:j]
        print(string_cut)
'''
while 1:
    try:
        string=input()
        palin_len=[]
        for i in range(len(string)):
            for j in range(i+1,len(string)):
                string_cut=string[i:j+1]
                for k in range(int(len(string_cut)/2)):
                    if string_cut[k]!=string_cut[-(k+1)]:
                        break
                else:
                    palin_len.append(len(string_cut))
        print(max(palin_len))

    except:
        break