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


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

	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
	#print(count)

	if prev_count < count:
		prev_count = count

print(prev_count)