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

[EX Q]: Sentence: 'an image of a cautionary construction sign'. Find frequency of the letter 'a'
[EX A]: 5

[EX Q]: Sentence: 'two baseball players high five each other during a game'. Find frequency of the letter 'y'
[EX A]: 1

[EX Q]: Sentence: 'a man standing on the beach flying a kite'. Find frequency of the letter 'g'
[EX A]:
2