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

[EX Q]: Sentence: 'the child is waving a small flag as she stands near two women'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'a woman and a child walking down a street with a kite'. Find frequency of the letter 'n'
[EX A]: 4

[EX Q]: Sentence: 'a man in a black shirt prepares to catch a frisbee'. Find frequency of the letter 'f'
[EX A]:
1