S = list(input())
l = len(S) -1


def solve(i,j):
	global S
	count = 0
	while i <= j:
		#print("i:",i,"j:",j)
		if S[i] == S[j]:
			if i == j:
				count += 1
			else:
				count += 2
		i += 1
		j -= 1

	return count

prev_count = 0
for i in range(l):
	for j in range(i+1):
		if prev_count >= l - i:
			print(prev_count)
			exit(0)

		count = solve(i+j,l-j)

		#print("count:",count)

		if prev_count < count:
			prev_count = count



print(prev_count)