{
	ll n,r=0,*v;
	rd(n);
	walloc1d(&v,n);
	rd(v(n));
	sort(v,v+n);
	do{
		ll s=0;
		rep(i,n/2)s+=v[i]^v[i+n/2];
		r=max(s,r);
		reverse(v+n/2,v+n);
	}while(next_permutation(v,v+n));
	wt(r);
}