#include <bits/stdc++.h>
using namespace std;
int arr[150];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  int ans = arr[0];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) {
      int now = 0;
      for (int k = i; k <= j; k++) now ^= arr[k];
      ans = max(ans, now);
    }
  cout << ans << endl;
  return 0;
}
