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

[Q]: Sentence: 'a group of people stand inside of a big room'. Find frequency of the letter 'o'
[A]: 6


[Q]: Sentence: 'small black bird with red on its head standing on a tree branch'. Find frequency of the letter 'b'
[A]: 3


[Q]: Sentence: 'two giraffe standing on a desert land scape'. Find frequency of the letter 'e'
[A]:
4