#include <bits/stdc++.h>
using namespace std;
int a[110];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
  }
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = i; j <= n; j++) {
      int tmp = a[i];
      for (int k = i + 1; k <= j; k++) tmp ^= a[k];
      ans = max(ans, tmp);
    }
  }
  printf("%d\n", ans);
  return 0;
}
