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;
int arr[100001];
int check(int j, int i) {
  int l = j - 1;
  int res = 0;
  int ress = 0;
  int fl = 1;
  while (l >= 0 && !(arr[l] & (1 << i))) {
    if (fl) {
      res = max(res, arr[l]);
      ress = arr[l] ^ arr[j];
      --l;
      fl = 0;
      continue;
    }
    if (arr[l] < res) {
      l--;
      continue;
    }
    res = max(res, arr[l]);
    ress = max(ress, arr[l] ^ arr[j]);
    --l;
  }
  fl = 1;
  l = j + 1;
  res = 0;
  while (l < n && !(arr[l] & (1 << i))) {
    if (fl) {
      res = max(res, arr[l]);
      ress = max(ress, arr[l] ^ arr[j]);
      ++l;
      fl = 0;
      continue;
    }
    if (arr[l] < res) {
      l++;
      continue;
    }
    res = max(res, arr[l]);
    ress = max(ress, arr[l] ^ arr[j]);
    ++l;
  }
  return ress;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> arr[i];
  }
  int res = 0;
  for (int i = 30; i >= 0; i--) {
    for (int j = 0; j < n; ++j) {
      if (arr[j] & (1 << i)) {
        if ((j - 1 >= 0 && !(arr[j - 1] & (1 << i))) ||
            (j + 1 < n && !(arr[j + 1] & (1 << i))))
          res = max(check(j, i), res);
      }
    }
    if (res > 0) break;
  }
  cout << res;
  return 0;
}
