read roadLength:int initialStones:int
gameloop
read trollDistance:int stones:int opponentStones:int
write 1

STATEMENT
Keep the troll out of your castle!

INPUT
roadLength: the distance (even) between both castles. The troll starts at half that distance.
initialStones: the number of stones each castle starts with.
trollDistance: distance between the troll and your castle. Keep it above zero!
stones: number of stones left.
opponentStones: number of stones left to your opponent.

OUTPUT
number of stones to shoot at the troll.