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

Example Input: Sentence: 'a box of a dozen doughnuts all varieties'. Replace the letter 'l' with 'i' in the sentence.
Example Output: a box of a dozen doughnuts aii varieties

Example Input: Sentence: 'a waterview with multiple boats in the water'. Replace the letter 'r' with 'w' in the sentence.
Example Output: a watewview with multiple boats in the watew

Example Input: Sentence: 'small group of colorful fruits next to each other'. Replace the letter 't' with 'i' in the sentence.
Example Output:
small group of colorful fruiis nexi io each oiher