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

[Q]: Sentence: 'two young ladies that are dancing in the room together'. Find frequency of the letter 'a'
[A]: 4


[Q]: Sentence: 'two boys are doing skateboard jumps in the street'. Find frequency of the letter 's'
[A]: 4


[Q]: Sentence: 'polar bear eating from a pile of carrots'. Find frequency of the letter 'l'
[A]:
2