You will be given a definition of a task first, then some input of the task.
In this task, you're given four sentences of a story written in natural language in which one part is missing. Your job is to predict the position and missing part of the story and return in the following format: position, missing part. The missing part is a sentence that completes the story, and the position is the number of the missing sentence in the new story.

Sentence1: I decided to add a new fountain pen to my collection. Sentence2: I'd seen online videos of a nice pen called a Pelikan M800. Sentence3: So I went to the pen shop at my local mall. Sentence4: I bought the pen.
Output:
4, The shop had just the model of pen I wanted.