Bike loves looking for the second maximum element in the sequence. The second maximum element in the sequence of distinct numbers x1, x2, ..., xk (k > 1) is such maximum element xj, that the following inequality holds: <image>.

The lucky number of the sequence of distinct positive integers x1, x2, ..., xk (k > 1) is the number that is equal to the bitwise excluding OR of the maximum element of the sequence and the second maximum element of the sequence.

You've got a sequence of distinct positive integers s1, s2, ..., sn (n > 1). Let's denote sequence sl, sl + 1, ..., sr as s[l..r] (1 ≤ l < r ≤ n). Your task is to find the maximum number among all lucky numbers of sequences s[l..r].

Note that as all numbers in sequence s are distinct, all the given definitions make sence.

Input

The first line contains integer n (1 < n ≤ 105). The second line contains n distinct integers s1, s2, ..., sn (1 ≤ si ≤ 109).

Output

Print a single integer — the maximum lucky number among all lucky numbers of sequences s[l..r].

Examples

Input

5
5 2 1 4 3


Output

7


Input

5
9 8 3 5 7


Output

15

Note

For the first sample you can choose s[4..5] = {4, 3} and its lucky number is (4 xor 3) = 7. You can also choose s[1..2].

For the second sample you must choose s[2..5] = {8, 3, 5, 7}.
#include <bits/stdc++.h>
using namespace std;
int n, m;
int i, j, k, l;
int a[111111];
pair<int, int> v[111111];
int main() {
  cin >> n;
  for (int _ = 0; _ < n; ++_) cin >> (a)[_];
  ;
  int x = 0;
  for (i = 0; i < n; ++i) v[i] = make_pair(a[i], i);
  sort(v, v + n);
  set<pair<int, int> > s;
  for (k = n - 1; k >= 0; --k) {
    pair<int, int> pp = make_pair(v[k].second, v[k].first);
    s.insert(pp);
    typeof(s.begin()) it = s.find(pp), it2;
    if (it != s.begin()) {
      it2 = it;
      --it2;
      x = max(x, it->second ^ it2->second);
    }
    it2 = it;
    ++it2;
    if (it2 != s.end()) {
      x = max(x, it->second ^ it2->second);
    }
  }
  cout << x << endl;
  return 0;
}
