$n=<>;
if($n>=16){
	print 65535;
	exit;
}
$h{0}=1;
for$a(glob<>){
	%h=map{$k=$_;map{$k|($a=$a*2%65535),1}0..15}keys%h;
}
for(reverse 0..65535){
	if($h{$_}){
		print;
		exit;
	}
}