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

[Q]: Sentence: 'a burning wood stove has a tea pot sitting on top of it and is full of wood'. Find frequency of the letter 'a'
[A]: 5

[Q]: Sentence: 'there is a stop sign that has a reflection in a puddle'. Find frequency of the letter 'e'
[A]: 5

[Q]: Sentence: 'close up of various doughnuts including chocolate, sprinkled, green, striped, etc'. Find frequency of the letter 'u'
[A]:
5