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: 'two little girls playing with a bat and a tennis ball'. Find frequency of the letter 'w'
[A]: 2

[Q]: Sentence: 'a social occasion of people are uncovered before the open day'. Find frequency of the letter 'c'
[A]:
4