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

[EX Q]: Sentence: 'two men with colorful ties are posing for a picture'. Find frequency of the letter 'r'
[EX A]: 4

[EX Q]: Sentence: 'a toilet sits in a cluttered bathroom next to a sink'. Find frequency of the letter 'a'
[EX A]: 4

[EX Q]: Sentence: 'a large jetliner landing on top of a runway'. Find frequency of the letter 'r'
[EX A]:
3