#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int a, b; cin >> a >> b;
	int N; cin >> N;
	int c = a ^ b;
	int m = 1;
	int aa = a, bb = b;
	while (c != a) {
		c = aa ^ bb;
		aa = bb;
		bb = c;
		m++;
	}
	N %= m;
	if (N == 0)
		cout << a << endl;
	else if (N == 1)
		cout << b << endl;
	else {
		rep(i, 0, N) {
			c = a ^ b;
			a = b;
			b = c;
		}
		cout << a << endl;
	}
	return 0;
}