#include <bits/stdc++.h>
using namespace std;
int main() {
  int arr[111], n;
  int res = 0;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &arr[i]);
  }
  for (int i = 0; i < n; i++) {
    int tmp = 0;
    for (int j = i; j < n; j++) {
      tmp ^= arr[j];
      if (tmp > res) res = tmp;
    }
  }
  printf("%d\n", res);
  return 0;
}
