$p=1;
<>;
for(glob<>){
	if($_==0){
		print -1;
		exit;
	}
	if($_>3){
		print 1000000007;
		exit;
	}
	$p*=(0,1,4,729)[$_];
	if($p>1000000007){
		print 1000000007;
		exit;
	}
}
print 1000000007%$p;