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

[Q]: Sentence: 'many white birds flying above a river that flows in front of a forest'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'
[A]: 1


[Q]: Sentence: 'people stand looking at sheep who had just been sheared'. Find frequency of the letter 'e'
[A]:
8