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

[EX Q]: Sentence: 'a person is riding in a cart pulled by a horse'. Find frequency of the letter 'a'
[EX A]: 4

[EX Q]: Sentence: 'an elephant has taken a man's hat in its trunk'. Find frequency of the letter 'p'
[EX A]: 1

[EX Q]: Sentence: 'the skateboarder is putting on a show using the picnic table as his stage'. Find frequency of the letter 't'
[EX A]:
7