#include <bits/stdc++.h>
using namespace std;
int a[105], b[105][105];
void solve() {
  int n;
  cin >> n;
  for (int i = 0; i <= n - 1; i++) cin >> a[i];
  for (int i = 0; i <= n - 1; i++)
    for (int j = i; j <= n - 1; j++)
      for (int k = i; k <= j; k++) b[i][j] ^= a[k];
  int maxm = -1;
  for (int i = 0; i <= n - 1; i++)
    for (int j = i; j <= n - 1; j++) {
      if (b[i][j] > maxm) {
        maxm = b[i][j];
      }
    }
  cout << maxm;
}
int main() {
  { solve(); }
  return 0;
}
