n = gets
until n.nil?
    classmember = Array.new(39,0)
    kyan = n.to_i
    i = 0
    kyan.times do
        classmember[i] += 1
        i += 1
        if i == 39
            i = 0
        end
    end
    howkyan = classmember.max
    num = classmember.rindex(howkyan)
    ansnum = num + 1
    if ansnum < 10
        ansnumm = ansnum.to_s
        ansnum = "0"+ansnumm
    end
    
    puts "3C#{ansnum}"

    n = gets
end
