So here we have a very long carbon backbone. So we can either begin counting this way or this way or this way. So we can say 123-45-6789 or 1234-5678 910. So it looks like if we go along this carbon backbone, we're going to have the longest carbon backbone. So we can either start from this end and go all the way down, or from this end and go all the way down. Since we want our substituent to have the lowest possible number, we should probably start to this end.