Detailed Instructions: In this task, you need to count the number of times the given letter appears in the given sentence.
See one example below:
Problem: Sentence: 'a large group of bananas proped up on several bicycles'. Find frequency of the letter 'e'
Solution: 5
Explanation: The letter 'e' appears 5 times in the sentence.

Problem: Sentence: 'a boy who is sitting on a couch watching television'. Find frequency of the letter 'c'
Solution:
3