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