c = gets.to_i.to_s(26)
c.length.times do |i|
    if c[i] >= "0" && c[i] <= "9"
        if i == 0 && i != c.length - 1
            c[i] = (c[i].ord + 16).chr
        else
            c[i] = (c[i].ord + 17).chr
        end
    else
        c[i] = (c[i].upcase.ord + 10).chr
    end
end
puts c