#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:1024000000,1024000000")
using namespace std;
int main() {
  int n, tmp, a[105], ans = 0;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
  }
  for (int i = 0; i < n; i++) {
    tmp = 0;
    for (int j = i; j < n; j++) {
      tmp = tmp ^ a[j];
      ans = max(tmp, ans);
    }
  }
  cout << ans << endl;
}
