#include <bits/stdc++.h>
using namespace std;
int a[110];
int main() {
  long long n, mid, ans = 0, mx = -INT_MAX;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) {
    for (int j = i; j <= n; j++) {
      ans = 0;
      for (int k = i; k <= j; k++) {
        ans = ans ^ a[k];
      }
      mx = max(ans, mx);
    }
  }
  cout << mx << endl;
}
