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

[Q]: Sentence: 'a full plate of food that includes rice and broccoli and carrots'. Find frequency of the letter 's'
[A]: 2


[Q]: Sentence: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'a large buffalo walking down a side walk'. Find frequency of the letter 'a'
[A]:
6