Abu and the Apples

Ankita has a pet monkey named Abu who has a really bad habit of stealing apples from their neighbour's tree. But as Abu is really young he's only able to steal apples which is at most $2$ branches away from the apple he started stealing with. Suppose, there are $A$ number of apples in their neighbour's tree marking from $1,2,3,....A$, and $B$ number of branches which connects any two of these app