#include <bits/stdc++.h>
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize(4)
using namespace std;
int n, a[105], ans;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
  for (int j = 1; j <= n; ++j) {
    int tmp = 0;
    for (int i = j; i <= n; ++i) {
      tmp ^= a[i];
      ans = max(ans, tmp);
    }
  }
  printf("%d\n", ans);
  return 0;
}
