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

[EX Q]: Sentence: 'a construction sign is displayed on a street'. Find frequency of the letter 'i'
[EX A]: 4

[EX Q]: Sentence: 'a blue fire hydrant painted on the bottom of it'. Find frequency of the letter 'h'
[EX A]: 2

[EX Q]: Sentence: 'man with gray beard about to enjoy pizza and a glass of red wine'. Find frequency of the letter 'i'
[EX A]:
3