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

[Q]: Sentence: 'a truck with a camper sits parked in some vegetation'. Find frequency of the letter 's'
[A]: 3

[Q]: Sentence: 'a dog laying on the back of a boat in the water'. Find frequency of the letter 't'
[A]: 4

[Q]: Sentence: 'a woman rests with two dogs on the bed with her'. Find frequency of the letter 'm'
[A]:
1