#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
int a[100005];
int main() {
  int n;
  int i, j;
  int sum = 0, count = 0;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d", &a[i]);
  for (i = 0; i < n; i++) {
    count = 0;
    for (j = i; j < n; j++) {
      count = count ^ a[j];
      sum = max(count, sum);
    }
  }
  printf("%d\n", sum);
  return 0;
}
