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>
unsigned int stack[100001];
unsigned int n, ele, max = 0, temp;
int top = -1;
void cmp(unsigned int ele);
int main() {
  scanf("%d", &n);
  while (n > 0) {
    scanf("%d", &ele);
    if (top == -1) {
      stack[++top] = ele;
    } else {
      while ((top != -1) && ele > stack[top]) {
        cmp(ele);
        top--;
      }
      cmp(ele);
      stack[++top] = ele;
    }
    n--;
  }
  printf("%u\n", max);
  return 0;
}
void cmp(unsigned int ele) {
  if (top != -1) {
    temp = (ele ^ stack[top]);
    max = (max > temp) ? max : temp;
  }
}
