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

[EX Q]: Sentence: 'a man on a skateboard going down a ramp while people are watching'. Find frequency of the letter 'w'
[EX A]: 3

[EX Q]: Sentence: 'a view from a bathroom shows an open door'. Find frequency of the letter 'o'
[EX A]: 7

[EX Q]: Sentence: 'a group of three buses driving down a highway'. Find frequency of the letter 'e'
[EX A]:
3