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

[EX Q]: Sentence: 'two giraffes, one standing and one laying down'. Find frequency of the letter 'g'
[EX A]: 3

[EX Q]: Sentence: 'two computers and a laptop set up on a desk'. Find frequency of the letter 'r'
[EX A]: 1

[EX Q]: Sentence: 'two zebras feed on a plant through some wire mesh'. Find frequency of the letter 'o'
[EX A]:
4