Instructions: 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.
Input: Sentence1: Until a mutual friend posted a picture of her in a restaurant. Sentence2: The picture brought Dan back to the good times. Sentence3: He felt regret. Sentence4: Dan decided to call his old girlfriend.
Output:
1, Dan was sure that he was over his ex girlfriend.