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

[EX Q]: Sentence: 'a yellow fire hydrant in the forefront of a roadway'. Find frequency of the letter 'r'
[EX A]: 5

[EX Q]: Sentence: 'a double-decker bus covered in children's illustrations driving next to a van'. Find frequency of the letter 'a'
[EX A]: 4

[EX Q]: Sentence: 'a man holding a pastry is accompanied by a guy wearing face paint'. Find frequency of the letter 'a'
[EX A]:
10