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

[EX Q]: Sentence: 'a man holding a brown paper bag kite'. Find frequency of the letter 'b'
[EX A]: 2

[EX Q]: Sentence: 'a glass bowl of raw broccoli, a ceramic bowl of raw green chili peppers, and steel bowl of raw daikon'. Find frequency of the letter 'a'
[EX A]: 9

[EX Q]: Sentence: 'a man in uniform standing next to machines'. Find frequency of the letter 'n'
[EX A]:
7