#include <bits/stdc++.h>
using namespace std;
const int oo = (int)1e9;
const double PI = 2 * acos(0.0);
const double eps = 1e-9;
int main() {
  ios_base::sync_with_stdio(false);
  int n, arr[110];
  cin >> n;
  for (int i = 0; i < (int)(n); i++) cin >> arr[i];
  int ans = 0, val = 0;
  for (int i = 0; i < (int)(n); i++) {
    val = 0;
    for (int k = i; k < (int)(n); k++) {
      val = val ^ arr[k];
      ans = max(ans, val);
    }
  }
  cout << ans << endl;
  return 0;
}
