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 microwave oven with a yellow note on the door'. Find frequency of the letter 'w'
[EX A]: 3

[EX Q]: Sentence: 'there are a number of parakeets in this cage'. Find frequency of the letter 'b'
[EX A]:
1