def solve():
    s = input()
    result = 0
    for i in range(1, len(s)):
        total = 0
        for c1, c2 in zip(s[i-1::-1], s[i:]):
            total += (c1 == c2)*2
        if result < total:
            result = total
        total = 1
        for c1, c2 in zip(s[i-1::-1], s[i+1:]):
            total += (c1 == c2)*2
        if result < total:
            result = total

    print(result)


if __name__ == "__main__":
    solve()