In this task, you are given two phrases: Head and Tail, separated with <sep>. The Head and the Tail events are short phrases possibly involving participants. The names of specific people have been replaced by generic words (e.g., PersonX, PersonY, PersonZ). PersonX is always the subject of the event. You have to determine whether the Head happens before the Tail or not. Classify your answers into "Yes" and "No". The phrase may also contain "___", a placeholder that can be an object, a person, and/or an action.

Ex Input:
Head: PersonX keeps PersonY in touch<sep>Tail: PersonX talks to him over facebook to see what he's doing

Ex Output:
Yes


Ex Input:
Head: PersonX dates back to the time<sep>Tail: PersonX writes it down in the book

Ex Output:
Yes


Ex Input:
Head: PersonX sounds interesting<sep>Tail: PersonX looks for more books

Ex Output:

Yes