#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int main(int argc, char* argv[])
{
	int N;
	cin>>N;
	vector<int> A(N);
	int i;
	for (i=0;i<N;i++){
		cin>>A[i];
	}
	sort(A.begin(),A.end());
	int Max=0;
	do {
		int s=0;
		for (i=0;i<N/2;i++){
			s+=A[i]^A[i+N/2];
		}
		Max=max(s,Max);
		reverse(A.begin()+N/2,A.end());
		s=0;
		for (i=0;i<N/2;i++){
			s+=A[i]^A[i+N/2];
		}
		Max=max(s,Max);
	}while(next_permutation(A.begin(),A.end()));
	cout<<Max<<endl;
	return 0;
}