Vladimir has white skin, very long teeth and is 600 years old, but this is no problem because Vladimir is a vampire.
Vladimir has never had any problems with being a vampire. In fact, he is a very successful doctor who always takes the night shift and so has made many friends among his colleagues. He has a very impressive trick which he shows at dinner partys: He can tell tell blood group by taste.
Vladimir loves to travel, but being a vampire he has to overcome three problems.
- First, he can only travel by train because he has to take his coffin with him. (On the up side he can always travel first class because he has invested a lot of money in long term stocks.)
- Second, he can only travel from dusk till dawn, namely from 6 pm to 6 am. During the day he has to stay inside a train station.
- Third, he has to take something to eat with him. He needs one litre of blood per day, which he drinks at noon (12:00) inside his coffin.
You should help Vladimir to find the shortest route between two given cities, so that he can travel with the minimum amount of blood. (If he takes too much with him, people will ask funny questions like "What do you do with all that blood?")