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

Input: Consider Input: Sentence: 'a yellow fire hydrant sitting on the sidewalk'. Replace the letter 'o' with 'd' in the sentence.

Output: a yelldw fire hydrant sitting dn the sidewalk

Input: Consider Input: Sentence: 'a geoup of people on bicycles coming down a street'. Replace the letter 'i' with 'x' in the sentence.

Output: a geoup of people on bxcycles comxng down a street

Input: Consider Input: Sentence: 'someone is holding a plate of food over a pool'. Replace the letter 'a' with 'x' in the sentence.
Output: someone is holding x plxte of food over x pool