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

[Q]: Sentence: 'a woman cross country skiing in a competition'. Find frequency of the letter 's'
[A]: 3


[Q]: Sentence: 'a gourmet looking hamburger with fries on a dining table with some wine'. Find frequency of the letter 't'
[A]: 4


[Q]: Sentence: 'close up of a crown of broccoli still in the ground'. Find frequency of the letter 'n'
[A]:
3