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

[Q]: Sentence: 'a half eaten doughnut in a persons hand'. Find frequency of the letter 'h'
[A]: 3


[Q]: Sentence: 'the wooden kitchen has a small child's plastic table in it'. Find frequency of the letter 'n'
[A]: 3


[Q]: Sentence: 'a bear who is resting its head on a rock'. Find frequency of the letter 'r'
[A]:
3