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 The names of specific people have been replaced by generic words (e.g., PersonX, PersonY, PersonZ).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.

Head: PersonX accidentally left<sep>Tail: He looked at his watch.
No

Head: PersonX serves PersonX's interests<sep>Tail: PersonX becomes president
Yes

Head: PersonX writes a letter to PersonY<sep>Tail: PersonX mails the letter to PersonY

Yes