def chara_match(instr):
	instr_rev = instr[::-1]
	s = 0
	for i in range(len(instr)):
		if instr_rev[i] == instr[i]:
			s += 1
	return s

s = input()
n = len(s)
ans = 0
for i in range(n):
	ans = max(ans, chara_match(s[0:i+1]))
for i in range(n):
	ans = max(ans, chara_match(s[i:n]))
print(ans)