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. And so let's start labeling or numbering. 1234-5678, 910. Okay, so that means we have ten, so that's decay.