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

[Q]: Sentence: 'silhouette of person playing frisbee with moutain and sunset'. Find frequency of the letter 'i'
[A]: 5

[Q]: Sentence: 'man in a sleeping bag on the floor using a laptop computer'. Find frequency of the letter 'i'
[A]: 3

[Q]: Sentence: 'a young girl sitting in a chair eating a doughnut'. Find frequency of the letter 'i'
[A]:
6