s = input()

count_max = -1
for i in range(1, len(s) - 1):
    count = 1
    for c1, c2 in zip(s[i - 1::-1], s[i + 1:]):
        if c1 == c2:
            count += 2
    count_max = max(count, count_max)

for i in range(len(s) - 1):
    count = 0
    for c1, c2 in zip(s[i::-1], s[i + 1:]):
        if c1 == c2:
            count += 2
    count_max = max(count, count_max)

print(count_max)