AI$-$Land is divided into $7$ regions. Two regions are said to be neighbors if they share an edge $($or a part of an edge $-$ e$.$g$.,2$ and $6$ are neighbors$).$ We want to color the regions using one of the $3$ colors $-$ Green, Yellow, or Purple so that no $2$ neighbors have the same color.

According to the heuristics discussed in the videos, which region should be colored first? $($If there is a tie between regions, choose the region with the least label number$)$