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

[Q]: Sentence: 'a mixed bouquet of flowers in a glass vase set before a window'. Find frequency of the letter 'w'
[A]: 3

[Q]: Sentence: 'a man and several white red and blue airplanes'. Find frequency of the letter 'u'
[A]: 1

[Q]: Sentence: 'there is a bowl of granola and a banana on a plate'. Find frequency of the letter 'o'
[A]:
4