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

[Q]: Sentence: 'a man holding a frisbee high into the air'. Find frequency of the letter 'a'
[A]: 4

[Q]: Sentence: 'this is an image of a woman playing tennis'. Find frequency of the letter 'f'
[A]: 1

[Q]: Sentence: 'giraffes are standing in the distance on a grassy land'. Find frequency of the letter 'a'
[A]:
7