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

[EX Q]: Sentence: 'a log in the water with three birds perched on it'. Find frequency of the letter 'r'
[EX A]: 4

[EX Q]: Sentence: 'three young people goofing around; one of the guys has a football, the girl has a teddy bear'. Find frequency of the letter 'd'
[EX A]: 3

[EX Q]: Sentence: 'a cat sitting on the edge of a bathroom sink'. Find frequency of the letter 'f'
[EX A]:
1