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: Sam wanted to get a dog. 
 Initial Context: So he was researching local pet stores to buy one. 
 Original Ending: It just so happened he logged onto Facebook to see an ad for a pound. A dog named Grump was going to be put down that day. Sam has a new best friend named Grump, you should meet him. 
 Counterfactual Context: So he went straight to the local pet store to buy one he liked.
Student:
He went on facebook while there and seen a ad for a pound, A dog named Grump was going to be put down that day. Sam has a new best friend named Grump, you should meet him. 