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: 'a bench along a forested hiking path'. Replace the letter 'd' with 'u' in the sentence.
Example Output: a bench along a foresteu hiking path

Example Input: Sentence: 'a fire hydrant in the middle of the grassy field'. Replace the letter 'h' with 'b' in the sentence.
Example Output:
a fire bydrant in tbe middle of tbe grassy field