#include <bits/stdc++.h>
using namespace std;
int a[105];
int main() {
  int n;
  cin >> n;
  int maxn = 0;
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }
  for (int i = 0; i < n; ++i) {
    int t = a[i];
    maxn = max(t, maxn);
    for (int j = 1; j + i < n; ++j) {
      t ^= a[i + j];
      maxn = max(t, maxn);
    }
  }
  cout << maxn << endl;
  return 0;
}
