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

[Q]: Sentence: 'a couple of men sitting next to each other under an umbrella'. Find frequency of the letter 'n'
[A]: 5


[Q]: Sentence: 'two pepperoni pizzas and a cup on a counter'. Find frequency of the letter 'u'
[A]: 2


[Q]: Sentence: 'a brown dog is laying on a dog bed with a teddy bear'. Find frequency of the letter 'w'
[A]:
2