#include <bits/stdc++.h>
int n, a[105], ans;
inline int Max(int x, int y) { return x > y ? x : y; }
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), a[i] ^= a[i - 1];
  for (int r = 1; r <= n; ++r)
    for (int l = 1; l <= r; ++l) ans = Max(ans, a[r] ^ a[l - 1]);
  printf("%d", ans);
  return 0;
}
