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

[EX Q]: Sentence: 'a double parking meter is decorated with a picture of a girl with wings on her feet'. Find frequency of the letter 'r'
[EX A]: 6

[EX Q]: Sentence: 'a person on a surfboard in the surf of a wave'. Find frequency of the letter 's'
[EX A]: 3

[EX Q]: Sentence: 'a cat sits on top of a stack of magazines'. Find frequency of the letter 's'
[EX A]:
4