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.

Premise: John and his father decided to build a robot. 
 Initial Context: They went the store and bought parts. 
 Original Ending: John's father taught John how to wire together the parts. It took all weekend, but they finished the robot! John and his father happily watched the robot move around. 
 Counterfactual Context: They went the store but couldn't find parts.
John's father can't taught John how to wire together the parts. It took all weekend to find the parts but they finished the robot! John and his father happily watched the robot move around. 