#include <bits/stdc++.h>
using namespace std;
int num[10000], maxx;
int main() {
  int n;
  scanf("%d", &n);
  int maxx = 0, t;
  for (int i = 0; i < n; ++i) {
    scanf("%d", &num[i]);
    for (int j = 0; j <= i; ++j) {
      t = 0;
      for (int k = j; k <= i; ++k) t = t ^ num[k];
      maxx = max(maxx, t);
    }
  }
  printf("%d\n", maxx);
}
