#include <bits/stdc++.h>
using namespace std;
int main() {
  int mas[105] = {0};
  int n;
  scanf("%d ", &n);
  int res = -1;
  int resl = -1;
  for (int i = 0; i < n; i++) scanf("%d ", &mas[i]);
  for (int i = 0; i < n; i++) {
    int len = 0;
    int mest = 0;
    for (int j = i; j < n; j++) {
      len++;
      mest ^= mas[j];
      if (mest > res) {
        res = mest;
        resl = len;
      }
    }
  }
  cout << res;
  return 0;
}
