#include <bits/stdc++.h>

/**
 * @title Binary trie
 * @docs binary_trie.md
 */
template <typename T, unsigned int B> class BinaryTrie{
protected:
  struct node{
    int count;
    node *ch[2];
    node(): count(0){
      ch[0] = ch[1] = nullptr;
    }
  };

  node *root = nullptr;

protected:
  int count(node *t) const {return t ? t->count : 0;}

  int count(node *t, T val, unsigned int depth = 1) const {
    if(!t) return 0;

    if(depth > B) return t->count;

    int b = (val >> (B - depth)) & 1;
    return count(t->ch[b], val, depth + 1);
  }
  
public:
  int count(T val) const {
    return count(root, val);
  }

public:
  int size() const {return root ? root->count : 0;}
  bool empty() const {return !root;}

protected:
  void to_list(node *t, T val, std::vector<T> &ret) const {
    if(!t) return;
    if(!t->ch[0] and !t->ch[1]) for(int i = 0; i < t->count; ++i) ret.push_back(val);

    if(t->ch[0]) to_list(t->ch[0], val<<1, ret);
    if(t->ch[1]) to_list(t->ch[1], (val<<1)|1, ret);
  }

public:
  std::vector<T> to_list() const {
    std::vector<T> ret;
    to_list(root, 0, ret);
    return ret;
  }

protected:
  node* insert(node *t, T val, unsigned int depth = 1){
    if(!t) t = new node();

    ++(t->count);
    if(depth > B) return t;

    int b = (val >> (B - depth)) & 1;
    t->ch[b] = insert(t->ch[b], val, depth + 1);
    return t;
  }
  
public:
  void insert(T val){
    root = insert(root, val);
  }
  
protected:
  node* erase(node *t, T val, unsigned int depth = 1){
    if(!t) return t;

    --(t->count);
    if(t->count == 0) return nullptr;
    if(depth > B) return t;

    int b = (val >> (B - depth)) & 1;
    t->ch[b] = erase(t->ch[b], val, depth + 1);
    return t;
  }
  
public:
  void erase(T val){
    root = erase(root, val);
  }

protected:
  T min_element(node *t, T diff, unsigned int depth = 1) const {
    if(depth > B) return 0;
    int b = (diff >> (B - depth)) & 1;
    b ^= !t->ch[b];
    return min_element(t->ch[b], diff, depth + 1) | (b << (B - depth));
  }
  
public:
  T min_element(T diff = 0) const {
    return min_element(root, diff);
  }

protected:
  T max_element(node *t, T diff, unsigned int depth = 1) const {
    if(depth > B) return 0;
    int b = !((diff >> (B - depth)) & 1);
    b ^= !t->ch[b];
    return max_element(t->ch[b], diff, depth + 1) | (b << (B - depth));
  }
  
public:
  T max_element(T diff = 0) const {
    return max_element(root, diff);
  }

protected:
  T at(node *t, int index, unsigned int depth = 1) const {
    if(depth > B) return 0;

    int c = count(t->ch[0]);
    if(t->ch[0] and index < c) return at(t->ch[0], index, depth + 1);
    else return at(t->ch[1], index - c, depth + 1) | ((T)1 << (B - depth));
  }

public:
  T at(int index) const {
    return at(index);
  }

protected:
  int lower_bound(node *t, T val, unsigned int depth = 1) const {
    if(!t) return 0;
    int b = (val >> (B - depth)) & 1;
    return (b ? count(t->ch[0]) : 0) + lower_bound(t->ch[b], val, depth + 1);
  }

public:
  int lower_bound(T val) const {
    return lower_bound(root, val);
  }

  int upper_bound(T val) const {
    return lower_bound(root, val + 1);
  }
};


int main(){
  int N;

  while(std::cin >> N){
    std::vector<int> A(N);
    for(int i = 0; i < N; ++i) std::cin >> A[i];


    BinaryTrie<int, 32> t;
    for(int i = 0; i < N; ++i) t.insert(A[i]);

    int ans = 0;
    for(int i = 0; i < N; ++i){
      ans = std::max(ans, t.max_element(A[i]) ^ A[i]);
    }

    std::cout << ans << "\n";
  }

  return 0;
}