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

Example Input: Sentence: 'a group of people walking along a dirty snow covered road'. Replace the letter 'n' with 'i' in the sentence.
Example Output: a group of people walkiig aloig a dirty siow covered road

Example Input: Sentence: 'stone and white colored structure in front of white modern building'. Replace the letter 'r' with 'p' in the sentence.
Example Output: stone and white coloped stpuctupe in fpont of white modepn building

Example Input: Sentence: 'a bowl of soup next to bread and some rice'. Replace the letter 'o' with 'y' in the sentence.
Example Output:
a bywl yf syup next ty bread and syme rice