Severe service disruptions are expected for all train traffic.

In spite of this strike announcement, the transport company is endeavouring to minimize the consequences of this strike as much as possible. To this end the company supplies a database of direct trains that are not affected. The database consists of facts of the form directTrain(A,B), indicating that passengers may trust that there is a train from A to B (not necessarily in the other direction).

Write a predicate travelFromTo(Start,End) that is true if it is possible to get form Start to End using the trains in the database.

To test your code, you can use this database¹