#include <bits/stdc++.h>
using namespace std;
int main() {
  long y, k, n, c, m, r, p, i, j;
  long ar[10000];
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> ar[i];
  }
  long s = 0, ans = 0;
  for (j = 0; j < n; j++, s = 0)
    for (i = j; i < n; i++) {
      s = s ^ ar[i];
      if (s > ans) ans = s;
    }
  cout << ans << endl;
  return 0;
}
