n=gets.to_i

=begin
(1..20).each do |m|
  s=0
  (1..m).each do |i|
    s^=i
  end
  puts "#{m} #{s}"
end

=end

if n<3
  puts 'O'
else
  n-=3
  if n%4==0
    puts 'X'
  else
    puts 'O'
  end
end