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

[Q]: Sentence: 'a man that is on his cell phone'. Find frequency of the letter 's'
[A]: 2

[Q]: Sentence: 'a young woman dressed in green and black operating a remote control'. Find frequency of the letter 'r'
[A]: 5

[Q]: Sentence: 'a large body of water filled with boats next to a tall building'. Find frequency of the letter 'y'
[A]:
1