#include<bits/stdc++.h>

 using namespace std;

 const int maxn = ;

 int n;

 int a[maxn];

 int bas[maxn];

 void read(){

     scanf("%d",&n);

     for(int i=;i<=n;i++) scanf("%d",&a[i]);

     sort(a+,a+n+);

 }

 void work(){

     long long ans = ;

     for(int i=n;i>=;i--){

         int dt = a[i];

         for(int j=;j>=;j--){

             if(!(a[i] & (<<j)))continue;

             if(bas[j] == ){bas[j] = a[i];break;}

             else a[i] ^= bas[j];

         }

         if(a[i] == ) ans += dt;

     }

     printf("%lld\n",ans);

 }

 int main(){

     read();

     work();

     return ;

 }