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

[EX Q]: Sentence: 'men are riding on motorcycles with a man riding in their carriers'. Find frequency of the letter 'r'
[EX A]: 8

[EX Q]: Sentence: 'a little dog on a table while a dog groomer cuts its fur'. Find frequency of the letter 'r'
[EX A]: 3

[EX Q]: Sentence: 'a snow filled mountain with a guy with ski's'. Find frequency of the letter 'f'
[EX A]:
1