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

[Q]: Sentence: 'a young boy standing in front of a counter with dougnuts'. Find frequency of the letter 'o'
[A]: 6


[Q]: Sentence: 'a small boat travels on the water next to the shore'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'a large grass pasture land with sheep grazing on grass'. Find frequency of the letter 'a'
[A]:
7