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

Example Input: Sentence: 'a tower type building structure with a large clock and many windows in front of a cloudy blue sky'. Replace the letter 'n' with 'x' in the sentence.
Example Output: a tower type buildixg structure with a large clock axd maxy wixdows ix froxt of a cloudy blue sky

Example Input: Sentence: 'broccoli and a sweet potato are served on a white plate'. Replace the letter 'o' with 'c' in the sentence.
Example Output: brccccli and a sweet pctatc are served cn a white plate

Example Input: Sentence: 'a variety of luggage is stacked in a compartment'. Replace the letter 'o' with 'r' in the sentence.
Example Output:
a variety rf luggage is stacked in a crmpartment