Definition: In this task, you're given a four sentences of story written in natural language. Your job is to complete end part of the story by predicting appropriate last sentence which is coherent with the given sentences.
Input: Sentence1: Bob moved from a small town to a large city. Sentence2: He was concerned he would always get lost. Sentence3: The first day he got lost trying to get home from work. Sentence4: Then Bob bought a navigation system to help him learn his way around.

The navigation system helped Bob a lot.