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

Example Input: Sentence: 'a chocolate cake decorated with strawberries on the side'. Replace the letter 'c' with 'x' in the sentence.
Example Output: a xhoxolate xake dexorated with strawberries on the side

Example Input: Sentence: 'a couple of kids are sitting in a field'. Replace the letter 't' with 'v' in the sentence.
Example Output: a couple of kids are sivving in a field

Example Input: Sentence: 'a skateboarder is in mid air doing a trick'. Replace the letter 'b' with 'x' in the sentence.
Example Output:
a skatexoarder is in mid air doing a trick