#include <bits/stdc++.h>
using namespace std;
template <class T>
T abs(T x) {
  return x > 0 ? x : -x;
}
int n;
int m;
vector<int> v;
int x[100000];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", &x[i]);
  for (int i = 29; i >= 0; i--) {
    v.clear();
    for (int j = 0; j < n; j++)
      if ((x[j] >> i) & 1) v.push_back(j);
    if (((int)(v).size()) > 0 && ((int)(v).size()) < n) {
      int ans = 0;
      for (int j = 0; j < ((int)(v).size()); j++) {
        int cur = 0;
        int tmp = 0;
        if (j > 0) tmp = v[j - 1] + 1;
        for (int k = v[j] - 1; k >= tmp; k--) {
          cur = max(cur, x[k]);
          ans = max(ans, cur ^ x[v[j]]);
        }
        cur = 0;
        tmp = n - 1;
        if (j + 1 < ((int)(v).size())) tmp = v[j + 1] - 1;
        for (int k = v[j] + 1; k <= tmp; k++) {
          cur = max(cur, x[k]);
          ans = max(ans, cur ^ x[v[j]]);
        }
      }
      printf("%d\n", ans);
      break;
    }
  }
  return 0;
}

### Prompt

Your challenge is to write a cpp solution to the following problem:

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}.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
template <class T>
T abs(T x) {
  return x > 0 ? x : -x;
}
int n;
int m;
vector<int> v;
int x[100000];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", &x[i]);
  for (int i = 29; i >= 0; i--) {
    v.clear();
    for (int j = 0; j < n; j++)
      if ((x[j] >> i) & 1) v.push_back(j);
    if (((int)(v).size()) > 0 && ((int)(v).size()) < n) {
      int ans = 0;
      for (int j = 0; j < ((int)(v).size()); j++) {
        int cur = 0;
        int tmp = 0;
        if (j > 0) tmp = v[j - 1] + 1;
        for (int k = v[j] - 1; k >= tmp; k--) {
          cur = max(cur, x[k]);
          ans = max(ans, cur ^ x[v[j]]);
        }
        cur = 0;
        tmp = n - 1;
        if (j + 1 < ((int)(v).size())) tmp = v[j + 1] - 1;
        for (int k = v[j] + 1; k <= tmp; k++) {
          cur = max(cur, x[k]);
          ans = max(ans, cur ^ x[v[j]]);
        }
      }
      printf("%d\n", ans);
      break;
    }
  }
  return 0;
}

```