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

Example Input: Sentence: 'a giraffe standing alone with a low fence behind it'. Replace the letter 't' with 'o' in the sentence.
Example Output: a giraffe soanding alone wioh a low fence behind io

Example Input: Sentence: 'three men in a park playing a sport'. Replace the letter 'p' with 'w' in the sentence.
Example Output: three men in a wark wlaying a swort

Example Input: Sentence: 'a kitchen sink, stove, toaster, pots, and pans'. Replace the letter 'o' with 'i' in the sentence.
Example Output:
a kitchen sink, stive, tiaster, pits, and pans