def fun(str_input):

max_len = 0
for i in range(len(str_input)):
    for j in range(len(str_input) - 1, i - 1, -1):
        if str_input[i: j + 1][::-1] == str_input[i: j + 1]:
            if j + 1 - i > max_len:
                max_len = j + 1 - i
return max_len

while True:

try:
    str_input = input()
    print(fun(str_input))
except:
    break