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

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

[EX Q]: Sentence: 'a picture of a machine built next to a street'. Find frequency of the letter 'x'
[EX A]: 1

[EX Q]: Sentence: 'two men and two women on sea beach,one pair is kissing each other'. Find frequency of the letter 'r'
[EX A]:
2