#include <bits/stdc++.h>
using namespace std;
int a[120], ans, i, j, n;
int main() {
  scanf("%d", &n);
  for (i = 1; i <= n; ++i) scanf("%d", &a[i]), a[i] ^= a[i - 1];
  for (i = 1; i <= n; ++i)
    for (j = i; j <= n; ++j) ans = max(ans, a[j] ^ a[i - 1]);
  printf("%d\n", ans);
}
