S = gets.chomp

def kaibun?(s, i, j)
  while i <= j do
    return false if s[i] != s[j]
    i += 1
    j -= 1
  end
  return true
end

max = 1
for i in 0..(S.length-2) do
  for j in i..(S.length-2) do
    next unless kaibun?(S, i, j)
    for k in (j+1)..(S.length-1) do
      for l in k..(S.length-1) do
        next unless kaibun?(S, k, l)
        len = [(j - i + 1), (l - k + 1)].max
        max = len if len > max
      end
    end
  end
end
puts max