#include <bits/stdc++.h>
using namespace std;
int ans = 0;
int n;
int ar[200];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> ar[i];
  for (int i = 0; i < n; i++) {
    int tmp = 0;
    for (int j = i; j < n; j++) {
      tmp = tmp ^ ar[j];
      ans = max(ans, tmp);
    }
  }
  cout << ans;
}
