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

[Q]: Sentence: 'an old glass vase containing flowers on a glass table'. Find frequency of the letter 'b'
[A]: 1


[Q]: Sentence: 'man in a radio studio wearing a suit in front of a microphone'. Find frequency of the letter 't'
[A]: 3


[Q]: Sentence: 'a man riding a skateboard in a bowl at a skateboard park'. Find frequency of the letter 'a'
[A]:
11