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

[EX Q]: Sentence: 'a baseball themed birthday cake is on a serving tray'. Find frequency of the letter 'g'
[EX A]: 1

[EX Q]: Sentence: 'a bird in a tree looking up at branches'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'a man holding a wii controller above his head and laughing'. Find frequency of the letter 'o'
[EX A]:
4