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

[EX Q]: Sentence: 'a tennis player that is running to get the tennis ball'. Find frequency of the letter 't'
[EX A]: 7

[EX Q]: Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'
[EX A]: 6

[EX Q]: Sentence: 'a herd of sheep grazing on grass in a pasture'. Find frequency of the letter 'a'
[EX A]:
5