s = input()

count_ls = []
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_ls.append(count)

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_ls.append(count)

print(max(count_ls))