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 had gotten a stink bomb from my cousin. 
 Initial Context: My plan was to set it off in math class. 
 Original Ending: When nobody sat in the desk I rigged up I got impatient. I went to talk to my friend as a way to hide breaking the vial. Within ten minutes we had to evacuate the class. 
 Counterfactual Context: I forgot  to set it off in math class.
Student:
When nothing happened at the desk I rigged up I got impatient. I went to talk to my friend as a way to hide breaking the vial. It took me ten minutes to realize I had forgot to set the vial. 