Teacher:Given a premise, an initial context, an original ending, and a counterfactual context, the task is to generate a new story ending aligned with the counterfactual context and as close to the original ending as possible. Each instance consists of a five-sentence story. The premise is the first sentence of a story, and the second sentence, which is the initial context, provides more information about the story's context and the story's general plot. The original ending is the last three sentences of the story. Also, a counterfactual context is a slight modification to the initial context. You should write a new story ending that edits the original story ending as little as possible to regain coherence with the counterfactual context. To sum up, you should write the last three sentences of a story based on the premise(first sentence) and the counterfactual context(second sentence) of the story.
Teacher: Now, understand the problem? Solve this instance: Premise: I walked to the mailbox to see if I got any mail. 
 Initial Context: There was only bills and a single personal letter. 
 Original Ending: The letter was addressed to a person I didn't know. I ripped open the letter and read it anyway. I wrote back to the sender and told him to not bother me. 
 Counterfactual Context: There were bills and lot of personal letters.
Student:
One of the letters was addressed to a person I didn't know. I ripped open the letter and read it anyway. I wrote back to the sender and told him to not bother me. 