Task: Story Composition
Input (English): Premise: Tom and Mary were baking an apple pie. 
 Initial Context: They chopped the apples. 
 Original Ending: They didn't have any butter. Mary went to the store to buy butter. The pie turned out very well. 
 New ending: They didn't have any apples. Mary went to the store to buy apples. The pie turned out very well. 
Output (English): They sliced the butter.