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

[EX Q]: Sentence: 'surfboard being displayed in stor window with clothes behind it'. Find frequency of the letter 't'
[EX A]: 4

[EX Q]: Sentence: 'a man holding a baseball bat an playing baseball'. Find frequency of the letter 'l'
[EX A]: 6

[EX Q]: Sentence: 'person doing skate tricks as people watch  him'. Find frequency of the letter 'a'
[EX A]:
3