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

Example Input: Sentence: 'a dog wearing a hat on top of it's head'. Replace the letter 'g' with 'o' in the sentence.
Example Output: a doo wearino a hat on top of it's head

Example Input: Sentence: 'a red park ride bus at a curb with a green/white bus behind'. Replace the letter 'h' with 'x' in the sentence.
Example Output: a red park ride bus at a curb witx a green/wxite bus bexind

Example Input: Sentence: 'a bicycle is parked outside of a stone building with a cat lying next to it'. Replace the letter 's' with 'p' in the sentence.
Example Output:
a bicycle ip parked outpide of a ptone building with a cat lying next to it