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

[Q]: Sentence: 'a herd of giraffe walking across a field'. Find frequency of the letter 'k'
[A]: 1


[Q]: Sentence: 'a small boat travels on the water next to the shore'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'a man on a tennis court at night time'. Find frequency of the letter 's'
[A]:
1