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

Example Input: Sentence: 'a group of sheep is standing in a grassy field'. Replace the letter 'g' with 'p' in the sentence.
Example Output: a proup of sheep is standinp in a prassy field

Example Input: Sentence: 'a white plate topped with two sandwich halves and a pile of potatoes chips'. Replace the letter 'o' with 'x' in the sentence.
Example Output: a white plate txpped with twx sandwich halves and a pile xf pxtatxes chips

Example Input: Sentence: 'a living room with a small luggage bag laying on top of a table in front of a sofa'. Replace the letter 's' with 'w' in the sentence.
Example Output:
a living room with a wmall luggage bag laying on top of a table in front of a wofa