S = raw_input()
ans = 0
for i in range(len(S) - 1):
	left,right = 1,1
	cnt = 1
	while i - left >= 0 and i + right < len(S) and S[i - left] == S[i + right]:
		cnt += 2
		left += 1
		right += 1
	ans = max(ans,cnt)
for i in range(len(S) - 1):
	left,right = i,i + 1
	cnt = 0
	while left >= 0 and right < len(S) and S[left] == S[right]:
		cnt += 2
		left -= 1
		right += 1
	ans = max(ans,cnt)
print ans