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

[Q]: Sentence: 'a group of cows that are standing in the grass'. Find frequency of the letter 'g'
[A]: 3


[Q]: Sentence: 'a stuffed animal sitting on an empty bed'. Find frequency of the letter 'u'
[A]: 1


[Q]: Sentence: 'the people are sampling wine at a wine tasting'. Find frequency of the letter 'i'
[A]:
4