#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  int max = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      int ct = arr[i];
      for (int k = i + 1; k <= j; k++) {
        ct = ct ^ arr[k];
      }
      if (ct > max) max = ct;
    }
  }
  cout << max;
}
