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

[EX Q]: Sentence: 'a train is sitting at a train station'. Find frequency of the letter 'r'
[EX A]: 2

[EX Q]: Sentence: 'the miniature, elaborate exhibit depicts an ancient boating scene'. Find frequency of the letter 'n'
[EX A]: 6

[EX Q]: Sentence: 'a woman training a horse inside a fenced area'. Find frequency of the letter 'e'
[EX A]:
5