In this task, you need to count the number of times the given letter appears in the given sentence.

[Q]: Sentence: 'town clocks affixed to a tall, brick building'. Find frequency of the letter 'r'
[A]: 1

[Q]: Sentence: 'a man holding a baseball bat an playing baseball'. Find frequency of the letter 'l'
[A]: 6

[Q]: Sentence: 'a baseball player in a blue shirt throwing a ball'. Find frequency of the letter 'e'
[A]:
3