#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  int* data = new int[n];
  for (int i = 0; i < n; i++) {
    scanf("%d", &data[i]);
  }
  int max = 0;
  for (int i = 0; i < n; i++) {
    int currentMax = 0;
    for (int j = i; j < n; j++) {
      currentMax = currentMax ^ data[j];
      if (currentMax > max) max = currentMax;
    }
  }
  printf("%d", max);
  return 0;
}
