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

Example Input: Sentence: 'a pile of chopped up broccoli sits next to bottles of sauces'. Replace the letter 't' with 'y' in the sentence.
Example Output: a pile of chopped up broccoli siys nexy yo boyyles of sauces

Example Input: Sentence: 'a red hydrant is sitting on the sidewalk in the city'. Replace the letter 'n' with 'r' in the sentence.
Example Output: a red hydrart is sittirg or the sidewalk ir the city

Example Input: Sentence: 'a man petting an elephant while holding a boy'. Replace the letter 'g' with 'x' in the sentence.
Example Output:
a man pettinx an elephant while holdinx a boy