#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, res = 0;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  for (int i = 0; i < n; ++i) {
    int x = v[i];
    for (int j = i + 1;; ++j) {
      if (x > res) res = x;
      if (j >= n) break;
      x ^= v[j];
    }
  }
  cout << res << endl;
  return 0;
}
