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

[EX Q]: Sentence: 'the street sign is next to a curved road'. Find frequency of the letter 's'
[EX A]: 3

[EX Q]: Sentence: 'a bus is stopped in front of a graphic statue'. Find frequency of the letter 'e'
[EX A]: 2

[EX Q]: Sentence: 'a fire hydrant is halfway sunk into the ground'. Find frequency of the letter 'f'
[EX A]:
2