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

[Q]: Sentence: 'a man working on a small laptop on a wooden table'. Find frequency of the letter 'l'
[A]: 4


[Q]: Sentence: 'a man that is on his cell phone'. Find frequency of the letter 's'
[A]: 2


[Q]: Sentence: 'a man in black jacket and hat holding cds'. Find frequency of the letter 'i'
[A]:
2