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

Example Input: Sentence: 'a herd of cattle standing on a lush green field'. Replace the letter 'g' with 'f' in the sentence.
Example Output: a herd of cattle standinf on a lush freen field

Example Input: Sentence: 'a study table with computer, mouse and keyboard .photo frame are also kept'. Replace the letter 'u' with 'q' in the sentence.
Example Output: a stqdy table with compqter, moqse and keyboard .photo frame are also kept

Example Input: Sentence: 'a plate of grilled vegetables and a hamburger'. Replace the letter 'r' with 'a' in the sentence.
Example Output:
a plate of gailled vegetables and a hambuagea