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

Example Input: Sentence: 'a boy on the beach playing with a frisbee'. Replace the letter 'h' with 'e' in the sentence.
Example Output: a boy on tee beace playing wite a frisbee

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 woman holding a cake with candles in front of a boy'. Replace the letter 'l' with 'z' in the sentence.
Example Output:
a woman hozding a cake with candzes in front of a boy