#include <bits/stdc++.h>
using namespace std;
const long long N = 1e3 + 5, M = 1e9 + 7;
long long a[N];
int main() {
  ios::sync_with_stdio(0), cin.tie(0);
  long long n, m = 0;
  cin >> n;
  for (long long i = 1; i <= n; i++)
    cin >> a[i], m = max(m, a[i]), a[i] ^= a[i - 1];
  for (long long i = 1; i <= n; i++)
    for (long long j = i + 1; j <= n; j++) m = max(m, a[j] ^ a[i - 1]);
  cout << m;
}
