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

[EX Q]: Sentence: 'a player swings his bat at a baseball game'. Find frequency of the letter 'p'
[EX A]: 1

[EX Q]: Sentence: 'some people sitting on surfboards in the water'. Find frequency of the letter 't'
[EX A]: 4

[EX Q]: Sentence: 'a green pasture with cattle spread around it'. Find frequency of the letter 'i'
[EX A]:
2

