#include <iostream>
#include <vector>
#include <bitset>
#include <algorithm>
using namespace std;
int main(){
  int N;cin>>N;
  vector<int> v1(N);
  int a=0;
  for(int i=0;i<N;++i){
    cin>>v1[i];
    if(a<v1[i]) a=v1[i];
  }
  bitset<33> bs1(a);
  int p=0;
  for(int i=32;i>=0;--i){
    if(bs1.test(i)){
      p=i;
      break;
    }
  }
  bitset<33> bs2=bs1;
  int c=a;
  while(1){
    c=(int)bs2.to_ulong();
    p-=1;
    vector<int> v2=v1;
    int b=0;
    for(int i=0;i<N;++i){
      v2[i]^=c;
      if(b<v2[i]) b=v2[i];
    }
    if(a>=b || p<0){
      break;
    } else {
      bs1.flip(p);
      bs2=bs1;
    }
  }
  int ans=0;
  for(int i=0;i<N;++i){
    v1[i]^=c;
    if(ans<v1[i]) ans=v1[i];
  }
  cout<<ans<<endl;
}