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

[EX Q]: Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'
[EX A]: 5

[EX Q]: Sentence: 'a herd of giraffe walking across a field'. Find frequency of the letter 'k'
[EX A]: 1

[EX Q]: Sentence: 'a polar bear is playing with a large chunk of ice'. Find frequency of the letter 'i'
[EX A]:
4