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

Example Input: Sentence: 'a black man is smoking a cigarette outside a shop'. Replace the letter 'm' with 'p' in the sentence.
Example Output: a black pan is spoking a cigarette outside a shop

Example Input: Sentence: 'a zebra patterned set of hair brushes sitting on each other'. Replace the letter 'r' with 'a' in the sentence.
Example Output: a zebaa patteaned set of haia baushes sitting on each othea

Example Input: Sentence: 'a red and black double decker bus next to a truck'. Replace the letter 'k' with 'y' in the sentence.
Example Output:
a red and blacy double decyer bus next to a trucy