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

[Q]: Sentence: 'a bird on a tree is flapping its wings'. Find frequency of the letter 'o'
[A]: 1


[Q]: Sentence: 'a woman standing in front of a bathroom sink in front of a mirror'. Find frequency of the letter 'o'
[A]: 8


[Q]: Sentence: 'a couple of wood benches are near a building'. Find frequency of the letter 'o'
[A]:
4