#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, A[200], ans = 0, sub = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> A[i];
  }
  for (int i = 0; i < n; i++) {
    sub = 0;
    for (int j = i; j < n; j++) {
      sub = sub ^ A[j];
      ans = max(sub, ans);
    }
  }
  cout << ans;
  return 0;
}
