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

[EX Q]: Sentence: 'a man riding his skateboard down low as he turns'. Find frequency of the letter 'g'
[EX A]: 1

[EX Q]: Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'brown animal sticking its face into the inside of a red rose'. Find frequency of the letter 'k'
[EX A]:
1