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

[EX Q]: Sentence: 'a person trying to flip a skateboard in a garage'. Find frequency of the letter 'a'
[EX A]: 7

[EX Q]: Sentence: 'a view from a bathroom shows an open door'. Find frequency of the letter 'o'
[EX A]: 7

[EX Q]: Sentence: 'two giraffes standing underneath a big tree with green leaves'. Find frequency of the letter 'i'
[EX A]:
4