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

[Q]: Sentence: 'a bunch of green bananas is hanging on a tree'. Find frequency of the letter 'n'
[A]: 7


[Q]: Sentence: 'a man and several white red and blue airplanes'. Find frequency of the letter 'u'
[A]: 1


[Q]: Sentence: 'there is a black bear that s walking in teh den'. Find frequency of the letter 'b'
[A]:
2