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

[EX Q]: Sentence: 'a cat sprawls out and sleeps on its back on a lounge chair with an acorn theme'. Find frequency of the letter 'r'
[EX A]: 3

[EX Q]: Sentence: 'a bed with a dog laying on it next to two laptop computers'. Find frequency of the letter 'n'
[EX A]: 3

[EX Q]: Sentence: 'a stop sign near a rail road crossing sign'. Find frequency of the letter 'g'
[EX A]:
3