In this task, you need to replace a letter in the sentence with another given letter.

Example Input: Sentence: 'a double decker bus stopped outside a station on a street'. Replace the letter 'c' with 'y' in the sentence.
Example Output: a double deyker bus stopped outside a station on a street

Example Input: Sentence: 'an image of a small galley-style kitchen pointed towards a skinny door'. Replace the letter 's' with 'i' in the sentence.
Example Output: an image of a imall galley-ityle kitchen pointed towardi a ikinny door

Example Input: Sentence: 'two men in front of a parking meter with an official'. Replace the letter 'a' with 'u' in the sentence.
Example Output:
two men in front of u purking meter with un officiul