#include <bits/stdc++.h>
using namespace std;
const int N = 105;
int a[N];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  int max1 = 0;
  for (int i = 1; i <= n; i++) {
    int sum = 0;
    for (int j = i; j <= n; j++) {
      sum = sum ^ a[j];
      max1 = max(max1, sum);
    }
  }
  printf("%d\n", max1);
}
