class A
  def initialize
    f0, f1, n = gets.chomp.split(' ').map(&:to_i)

    f0 = "%019b" % [f0]
    f1 = "%019b" % [f1]

    answer = ""

    18.downto(0) do |index|
      ch1 = f0[index]
      ch2 = f1[index]

      if ch1 == '0' && ch2 == '0'
        answer << '0'
      elsif ch1 == '0' && ch2 == '1'
        answer << ['1','0','1'][(n-2)%3]
      elsif ch1 == '1' && ch2 == '0'
        answer << ['1','1','0'][(n-2)%3]
      else
        answer << ['0','1','1'][(n-2)%3]
      end
    end

    if n == 0
      puts f0.to_i(2)
    elsif n == 1
      puts f1.to_i(2)
    else
      puts answer.reverse.to_i(2)
    end
  end
end

A.new