#include <bits/stdc++.h>
const double PI = acos(-0);
const int mod = 1000007;
const int maxn = 1e5 + 10;
const int inf = 0x3f3f3f3f;
const int NEXT[][2] = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
using namespace std;
int a[101];
int main() {
  int n;
  int ans, k;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
  }
  ans = 0;
  for (int i = 0; i < n; i++) {
    k = 0;
    for (int j = i; j < n; j++) {
      k ^= a[j];
      ans = max(k, ans);
    }
  }
  printf("%d\n", ans);
}
