#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)

void bit_print(int x) {
  vector<int> b;
  while(x > 0) {
    b.push_back(x & 1);
    x >>= 1;
  }
  reverse(b.begin(), b.end());
  rep(i, b.size()) {
    cout << b[i];
  }cout << endl;
}

int main() {
  
  int f0, f1, f2, N; cin >> f0 >> f1 >> N;
  f2 = f0 ^ f1;
  /*
  cout << "---------------\n";
  bit_print(f0);  bit_print(f1);  bit_print(f2);
  cout << "---------------\n";
  */
  vector<int> v;
  rep(i, 3) {
    f2 = f0 ^ f1;
    //    bit_print(f2);
    f0 = f1, f1 = f2;
    v.push_back(f2);
  }
  int fn;
  if(N % 3 == 0) { fn = v[1]; }
  if(N % 3 == 1) { fn = v[2]; }
  if(N % 3 == 2) { fn = v[0]; }
  cout << fn << endl;
  
  return 0;
}