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

Example Input: Sentence: 'this is a tennis player getting ready to serve the ball'. Replace the letter 'h' with 'y' in the sentence.
Example Output: tyis is a tennis player getting ready to serve tye ball

Example Input: Sentence: 'a boy riding his skate board on an obstacle course'. Replace the letter 'e' with 'b' in the sentence.
Example Output: a boy riding his skatb board on an obstaclb coursb

Example Input: Sentence: 'oranges and onions are on display at a farmers market'. Replace the letter 'n' with 'h' in the sentence.
Example Output:
orahges ahd ohiohs are oh display at a farmers market