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

[Q]: Sentence: 'a few giraffes standing in a field looking around'. Find frequency of the letter 'e'
[A]: 3

[Q]: Sentence: 'a young boy holding a piece of paper on top of a table'. Find frequency of the letter 'y'
[A]: 2

[Q]: Sentence: 'a group of men standing and sitting with sitting men holding up a cake'. Find frequency of the letter 's'
[A]:
3