fun main(arr:Array<String>) {
    val (f0,f1, n) = readLine()!!.split(" ").map { it.toInt() }
    val temp = mutableListOf<Int>()
    temp.add(f0)
    temp.add(f1)
    temp.add(f0 xor f1)
    val ans = temp[n % 3]
    println(ans)
}