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

Example Input: Sentence: 'a red stop signed has been altered to say stop hate'. Replace the letter 'e' with 't' in the sentence.
Example Output: a rtd stop signtd has bttn alttrtd to say stop hatt

Example Input: Sentence: 'a large clock tower next to a building on a street'. Replace the letter 'c' with 'n' in the sentence.
Example Output: a large nlonk tower next to a building on a street

Example Input: Sentence: 'a bench sitting on top of some steps by a wall'. Replace the letter 'i' with 'b' in the sentence.
Example Output:
a bench sbttbng on top of some steps by a wall