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

[Q]: Sentence: 'a picture of a toilet and toilet paper in a bathroom'. Find frequency of the letter 'o'
[A]: 5

[Q]: Sentence: 'hand holding a white calculator inside a store'. Find frequency of the letter 'o'
[A]: 3

[Q]: Sentence: 'a man in tie, black coat and a hat'. Find frequency of the letter 'n'
[A]:
3