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

[EX Q]: Sentence: 'a bed with a mattress that has nothing on it'. Find frequency of the letter 'a'
[EX A]: 5

[EX Q]: Sentence: 'two elephants walking on cement next to wall'. Find frequency of the letter 'n'
[EX A]: 5

[EX Q]: Sentence: 'a variety of vegetables laid out on a kitchen counter'. Find frequency of the letter 'e'
[EX A]:
6