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

[Q]: Sentence: 'a plastic plastic plate topped with three different type of food'. Find frequency of the letter 'l'
[A]: 3


[Q]: Sentence: 'cars parked outside if a retail store'. Find frequency of the letter 'd'
[A]: 2


[Q]: Sentence: 'the man is dressed in a suit while playing his guitar'. Find frequency of the letter 'a'
[A]:
4