func main()
	var f: []int :: #[2]int
	do f[0] :: cui@inputInt()
	do f[1] :: cui@inputInt()
	var n: int :: cui@inputInt()
	var ans: int
	switch i(n % 3)
	case 2
		do ans :: f[0] $ bit64.xor(f[1] $ bit64) $ int
	default
		do ans :: f[i]
	end switch
	do cui@print("\{ans}\n")
end func