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

[EX Q]: Sentence: 'a man hitting a tennis ball with a tennis racquet'. Find frequency of the letter 't'
[EX A]: 6

[EX Q]: Sentence: 'an elephant has taken a man's hat in its trunk'. Find frequency of the letter 'p'
[EX A]: 1

[EX Q]: Sentence: 'a large yak is standing alone on a beach'. Find frequency of the letter 'n'
[EX A]:
4