inputed_list = list(input())

res = 1
tmp_list = []
for i in range(len(inputed_list)):
    tmp_list.clear()
    for e in inputed_list:
        tmp_list.append(e)
    j = 1
    length = 1

    while True:
        if i - j < 0 or i + j >= len(inputed_list):
            break
        b = tmp_list[i - j]
        f = tmp_list[i + j]
        if b == f:
            length += 1
            res = max(res, length)
            j += 1
        else:
            tmp_list[i - j] = ' '
            tmp_list[i + j] = ' '
            j += 1

if res == 1:
    print(0)
elif res % 2 == 1:
    print(res * 2 - 1)
else:
    print(res * 2)