A1012.Fruit Feast--Gold

Bessie has broken into Farmer John's house again! She has discovered a pile of
lemons and a pile of oranges in the kitchen (effectively an unlimited number
of each), and she is determined to eat as much as possible.
Bessie has a maximum fullness of $T$ ($1 \le T \le 5,000,000$). Eating an
orange increases her fullness by $A$, and eating a lemon increases her
fullness by $B$ ($1 \le A, B \le T$). Additionally, if she wants, Bessie can
drink water at most one time, which will instantly decrease her fullness by
half (and will round down).
Help Bessie determine the maximum fullness she can achieve!

The first (and only) line has three integers $T$, $A$, and $B$.

A single integer, representing the maximum fullness Bessie can achieve.