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

[EX Q]: Sentence: 'apples, pears, and oranges are piled up for sale'. Find frequency of the letter 'a'
[EX A]: 6

[EX Q]: Sentence: 'a bus with two floors belonging to london country'. Find frequency of the letter 't'
[EX A]: 4

[EX Q]: Sentence: 'there is a man holding a umbrella sitting looking'. Find frequency of the letter 'k'
[EX A]:
1