s = gets.strip
@len_max = 0
def search(s, len_max, num)
	#p s
	if s.length == 0 && num > 1
		@len_max = [@len_max, len_max].max
		#p @len_max
		return
	end
	(0...s.length).each do |i|
		if s[0..i] == s[0..i].reverse
			#print "#{s[0..i]} OK\n"
			len_max = [len_max, s[0..i].length].max
			search(s[i + 1..-1], len_max, num + 1)
		end
	end
	
end

if s.length == 2
	puts "1"
else	
	search(s, 0, 0)
	p @len_max
end