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

[Q]: Sentence: 'a couple of boys in a field playing baseball'. Find frequency of the letter 'i'
[A]: 3


[Q]: Sentence: 'a mixed bouquet of flowers in a glass vase set before a window'. Find frequency of the letter 'w'
[A]: 3


[Q]: Sentence: 'a group of men working together in a kitchen'. Find frequency of the letter 'g'
[A]:
3