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

[Q]: Sentence: 'a girl that has a kite in the air'. Find frequency of the letter 'r'
[A]: 2


[Q]: Sentence: 'a bus is stopped in front of a graphic statue'. Find frequency of the letter 'e'
[A]: 2


[Q]: Sentence: 'a man flying through the air on a bicycle'. Find frequency of the letter 'u'
[A]:
1