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