#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  ll n, k;
  cin >> n >> k;
  vector<ll> a(n + 1);
  rep(i, n) cin >> a[i], a[n] ^= a[i];
  cout << a[(k - 1) % (n + 1)] << '\n';
  return 0;
}