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

Example Input: Sentence: 'a man getting ready to hit a ball at a baseball game'. Replace the letter 'n' with 'v' in the sentence.
Example Output: a mav gettivg ready to hit a ball at a baseball game

Example Input: Sentence: 'you are never to old to play with the nintendo wii'. Replace the letter 'e' with 'v' in the sentence.
Example Output: you arv nvvvr to old to play with thv nintvndo wii

Example Input: Sentence: 'white toilet bowl sitting on the side of a road by a van'. Replace the letter 'b' with 'r' in the sentence.
Example Output:
white toilet rowl sitting on the side of a road ry a van