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

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

[EX Q]: Sentence: 'a group of men standing around a table cutting a cake'. Find frequency of the letter 'g'
[EX A]: 3

[EX Q]: Sentence: 'a crowd of people stand around the plane'. Find frequency of the letter 'u'
[EX A]:
1