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

[EX Q]: Sentence: 'a crowd of people standing in front of a green train'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'a man flying through the air on top of a skateboard'. Find frequency of the letter 'h'
[EX A]: 3

[EX Q]: Sentence: 'a l shaped couch in the living room'. Find frequency of the letter 'l'
[EX A]:
2