#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> arr(n);
  for (int i = 0; i < n; ++i) cin >> arr[i];
  int max = 0;
  for (int i = 0; i < n; ++i) {
    int curr = 0;
    for (int j = i; j < n; ++j) {
      curr ^= arr[j];
      if (curr > max) max = curr;
    }
  }
  cout << max << endl;
  return 0;
}
