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

[EX Q]: Sentence: 'a person riding a skate board on a city street'. Find frequency of the letter 'a'
[EX A]: 5

[EX Q]: Sentence: 'a passenger train that is going over a bridge'. Find frequency of the letter 't'
[EX A]: 3

[EX Q]: Sentence: 'a lady playing tennis outside during a sunny day'. Find frequency of the letter 'r'
[EX A]:
1