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

[EX Q]: Sentence: 'a crowd of fans watch soccer players from stadium seating'. Find frequency of the letter 'f'
[EX A]: 3

[EX Q]: Sentence: 'a woman with short, brown hair is looking into a circular mirror and holding a camera up to her cheek'. Find frequency of the letter 'e'
[EX A]: 4

[EX Q]: Sentence: 'three boats are docked at a wooden deck on a lake'. Find frequency of the letter 'k'
[EX A]:
3