($N,@M)=<>;
@q=0;
while(@q){
	$q=shift@q;
	for(0..$#M){
		if(not$q&1<<$_){
			if(defined$p[$Q=$q|1<<$_]){
				$p[$Q]-=$-=$p[$Q]-($p[$q]+($-=$M[$_]-$m[$q]));
			}else{
				$p[$Q]=$p[$q]+($-=$M[$_]-$m[$q]);
				$m[$Q]=($m[$q]+$M[$_])%1000;
				push@q,$Q;
			}
		}
	}
}
print$p[(1<<$N)-1]