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

Example Input: Sentence: 'a red park ride bus at a curb with a green/white bus behind'. Replace the letter 'h' with 'x' in the sentence.
Example Output: a red park ride bus at a curb witx a green/wxite bus bexind

Example Input: Sentence: 'a couple sits on a bench in the countryside'. Replace the letter 'y' with 'k' in the sentence.
Example Output: a couple sits on a bench in the countrkside

Example Input: Sentence: 'a man on a tennis court hitting a ball with his racket'. Replace the letter 'i' with 'w' in the sentence.
Example Output:
a man on a tennws court hwttwng a ball wwth hws racket