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

[EX Q]: Sentence: 'the two dogs are playing in the pen together'. Find frequency of the letter 'o'
[EX A]: 3

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

[EX Q]: Sentence: 'a giraffe stands between a couple of bushes'. Find frequency of the letter 's'
[EX A]:
4