Given the task definition and input, reply with output. 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.

Sentence1: Anna was having a picnic on the beach. Sentence2: She laid out the chips and snacks on the blanket. Sentence3: Then everyone went for a swim before eating. Sentence4: But when they returned, all of their food was gone.
Seagulls had stolen everything!