#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
int n;
int a[105];
int main() {
  ios::sync_with_stdio(false);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  int mx = 0;
  for (int i = 1; i <= n; i++) {
    int tmp = 0;
    for (int j = i; j <= n; j++) {
      tmp ^= a[j];
      mx = max(mx, tmp);
    }
  }
  cout << mx << endl;
  return 0;
}
