#include <bits/stdc++.h>
using namespace std;
const int N = 4e6 + 123;
const int NN = 1e3 + 123;
const int INF = 1e9 + 123;
const int MOD = 1e9 + 7;
const double EPS = 1e-9;
long long d, a[N], n, m, ans, cnt = 1, sum, mx;
vector<long long> v;
int main() {
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; ++i) {
    sum = a[i];
    mx = max(mx, sum);
    for (int j = i + 1; j <= n; ++j) {
      sum ^= a[j];
      mx = max(mx, sum);
    }
    sum = 0;
  }
  cout << mx;
  return 0;
}
