Task: Sentence Ordering
Input (English): Sentence1: Lewis knew the cave like the back of his hand. Sentence2: Five first-time cavers walked behind him. Sentence3: Lewis laughed and told them not be afraid of the bats. Sentence4: All the people but Lewis ran back towards the cave's entrance. Sentence5: Suddenly, a few bats flew down from the darkness above.
Output (English): 12543