#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int main() {
  long long int test, m, n = 0, k = 0, arr[1010] = {0}, max = 0,
                         ans[101][101] = {0};
  scanf("%Ld", &n);
  for (long long int i = (0); i < (n); i++) {
    scanf("%Ld", &arr[i]);
  }
  for (long long int i = (0); i < (n); i++)
    for (long long int j = (i); j < (n); j++) {
      if (j - 1 >= i)
        ans[i][j] = ans[i][j - 1] ^ arr[j];
      else
        ans[i][j] = arr[i];
    }
  for (long long int i = (0); i < (n); i++)
    for (long long int j = (0); j < (n); j++)
      if (max < ans[i][j]) max = ans[i][j];
  printf("%Ld\n", max);
  return 0;
}
