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

[Q]: Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'
[A]: 3


[Q]: Sentence: 'a group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'
[A]: 3


[Q]: Sentence: 'a drink and some food sit next to paper and scissors'. Find frequency of the letter 'o'
[A]:
5