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

[EX Q]: Sentence: 'a small boy in a high chair eating a cupcake'. Find frequency of the letter 'i'
[EX A]: 4

[EX Q]: Sentence: 'a birthday cake with a number one and three candle'. Find frequency of the letter 'w'
[EX A]: 1

[EX Q]: Sentence: 'there is a baseball game on and a few people are watching'. Find frequency of the letter 'i'
[EX A]:
2