#include <bits/stdc++.h>
int a[105];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  int s = 0;
  for (int i = 0; i < n; ++i) {
    int t = 0;
    for (int j = i; j < n; ++j) {
      t ^= a[j];
      if (s < t) s = t;
    }
  }
  printf("%d\n", s);
  return 0;
}
