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

Example Input: Sentence: 'many street signs in front of a building while it is snowing'. Replace the letter 'r' with 'x' in the sentence.
Example Output: many stxeet signs in fxont of a building while it is snowing

Example Input: Sentence: 'a police officer on a horse is riding down the street'. Replace the letter 'h' with 'a' in the sentence.
Example Output: a police officer on a aorse is riding down tae street

Example Input: Sentence: 'a red bus with a sign on it for advertising traveling down the street'. Replace the letter 'w' with 'i' in the sentence.
Example Output:
a red bus iith a sign on it for advertising traveling doin the street