Bipartite Graphs and Matchings · Easy problem

A network wires nine computers $1,2,\dots,9$ as a tree: the path $1\text{-}2\text{-}3\text{-}4\text{-}5\text{-}6$, together with three extra direct links, $7$ to $2$, $8$ to $5$, and $9$ to $1$. Every tree is bipartite, so the nine computers split into two groups with every wire joining one group to the other. What is the size of the LARGER group?