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

Example Input: Sentence: 'a baseball player swinging a bat at a ball'. Replace the letter 's' with 'n' in the sentence.
Example Output: a baneball player nwinging a bat at a ball

Example Input: Sentence: 'this is a cute dog sticking his head out of the window of a red car'. Replace the letter 'e' with 'z' in the sentence.
Example Output: this is a cutz dog sticking his hzad out of thz window of a rzd car

Example Input: Sentence: 'a dog is standing on top of a chair'. Replace the letter 's' with 'p' in the sentence.
Example Output:
a dog ip ptanding on top of a chair