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

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

[Q]: Sentence: 'a man pushing a cart full of bananas'. Find frequency of the letter 'u'
[A]: 2

[Q]: Sentence: 'a old red fire hydrain that is next to a street'. Find frequency of the letter 'a'
[A]:
4