#include <bits/stdc++.h>
using namespace std;
int a[101], ans;
int main() {
  int n;
  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++) {
      int sum = 0;
      for (int k = i; k <= j; k++) {
        sum = sum ^ a[k];
      }
      ans = max(sum, ans);
    }
  }
  cout << ans;
  return 0;
}
