In this task, you're given a pair of sentences, sentence 1 and sentence 2, that neither agree with nor contradict each other. Your job is to alter sentence 2 so that the pair clearly contradict each other. Generated sentences must be short, with less than 15 words. New information can be introduced. Avoid using pronouns to confuse the subject of the sentence.

Example Input: Sentence 1: A door in a tall concrete wall Sentence 2: A door in a wall of at stone building.
Example Output: A door in a wall.

Example Input: Sentence 1: A white dog walking beside a bicycler. Sentence 2: A puppy is running
Example Output: A dog walking beside a person on a bike.

Example Input: Sentence 1: A small boy climbing a backyard play set. Sentence 2: A boy is playing on the swing-set.
Example Output:
A boy with his tongue out is holding onto a bar.