#include <bits/stdc++.h>
using namespace std;
int main() {
  long int a[101];
  long int m = 0, c = 0, i, j, n;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    m = max(m, a[i]);
  }
  for (i = 0; i < n; i++) {
    c = a[i];
    for (j = i + 1; j < n; j++) {
      c ^= a[j];
      m = max(m, c);
    }
  }
  cout << m;
}
