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

[EX Q]: Sentence: 'a person that is looking out his window'. Find frequency of the letter 'n'
[EX A]: 3

[EX Q]: Sentence: 'a log in the water with three birds perched on it'. Find frequency of the letter 'r'
[EX A]: 4

[EX Q]: Sentence: 'a market with grape, kiwi, apples, peaches, cantaloupe and a pumpkin'. Find frequency of the letter 'p'
[EX A]:
7