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

[EX Q]: Sentence: 'a car accident has slowed traffic as a clean up crew works'. Find frequency of the letter 'f'
[EX A]: 2

[EX Q]: Sentence: 'a bird outside standing on a table looking up'. Find frequency of the letter 'b'
[EX A]: 2

[EX Q]: Sentence: 'inside house living room and dining room with furniture'. Find frequency of the letter 'd'
[EX A]:
3