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