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

[Q]: Sentence: 'a man serving himself pizza in a wooden booth'. Find frequency of the letter 'n'
[A]: 4

[Q]: Sentence: 'a man skating down a stair rail in front of a bunch of people'. Find frequency of the letter 'o'
[A]: 5

[Q]: Sentence: 'panorama of different colored sheep grazing in a field'. Find frequency of the letter 'e'
[A]:
6