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

[Q]: Sentence: 'a group of people standing on grass with a train in the background'. Find frequency of the letter 'n'
[A]: 6


[Q]: Sentence: 'a wedding cake with pink roses on a silver plate'. Find frequency of the letter 'a'
[A]: 4


[Q]: Sentence: 'two women wearing summer clothes stand with rackets in the sand'. Find frequency of the letter 'k'
[A]:
1