import java.io.BufferedReader
import java.io.BufferedWriter
private lateinit var bufferedReader: BufferedReader
private lateinit var bufferedWriter: BufferedWriter
fun main() {
bufferedReader = System.`in`.bufferedReader()
bufferedWriter = System.out.bufferedWriter()
// 1. get (a, b, c)
val (a, b, c) = bufferedReader
.readLine()
.split(" ")
.map { it.toInt() }
var answer = a
// 2. c가 홀수인 경우에만 xor 한번 해주면 됩니다.
if (c and 1 == 1) answer = answer xor b
bufferedWriter.write("$answer")
bufferedReader.close()
bufferedWriter.close()
}