#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j;
  cin >> n;
  int ar[n + 1], max = 0, tmp;
  for (i = 0; i < n; i++) {
    cin >> ar[i];
  }
  for (i = 0; i < n; i++) {
    tmp = 0;
    for (j = i; j < n; j++) {
      tmp = tmp ^ ar[j];
      if (tmp > max) max = tmp;
    }
  }
  cout << max;
}
