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

[EX Q]: Sentence: 'party cakes in plastic containers, with a cake with a plastic santa claus and reindeer on top'. Find frequency of the letter 's'
[EX A]: 6

[EX Q]: Sentence: 'a blue tripocal bird is perched on a wooden fence'. Find frequency of the letter 'd'
[EX A]: 3

[EX Q]: Sentence: 'a person holding a bottle of drink and a hotdog in a napkin at a hot dog stand'. Find frequency of the letter 'i'
[EX A]:
4