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

[EX Q]: Sentence: 'baseball player reaching back as he's about to throw the ball'. Find frequency of the letter 'e'
[EX A]: 5

[EX Q]: Sentence: 'a man in costume talking on a cell phone'. Find frequency of the letter 'm'
[EX A]: 2

[EX Q]: Sentence: 'a large elephant standing next to a wire fence'. Find frequency of the letter 'l'
[EX A]:
2