1 #include<cstdio>
 2 #include<iostream>
 3 using namespace std;
 4 const int sz = 100010;
 5 int n, tot = 0;
 6 int trie[sz*32][2], a[sz];
 7 void insert(int x) {
 8     int root = 0;
 9     for(int i = 31; i >= 0; i--) {
10         int id = (x>>i)&1;
11         if(!trie[root][id]) trie[root][id] = ++tot;
12         root = trie[root][id];
13     }
14 }
15 int search(int x) {
16     int root = 0, sum = 0;
17     for(int i = 31; i >= 0; i--) {
18         int id = (x>>i)&1;
19         if(trie[root][id^1]) {
20             root = trie[root][id^1];
21             sum = (sum<<1)|1;
22         }
23         else {
24             root = trie[root][id];
25             sum = sum<<1;
26         }
27     }
28     return sum;
29 }
30 int main() {
31     int ans = 0;
32     scanf("%d", &n);
33     for(int i = 1; i <= n; i++) {
34         scanf("%d", &a[i]);
35         insert(a[i]);
36     }
37     for(int i = 1; i <= n; i++) {
38         if(search(a[i])>ans) {
39             ans = search(a[i]);
40         }
41     }
42     printf("%d\n", ans);
43     return 0;
44 }