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

[EX Q]: Sentence: 'an empty clean kitchen with island, marble countertops , stove and cabinetry'. Find frequency of the letter 'l'
[EX A]: 3

[EX Q]: Sentence: 'man sitting on the side of a van playing the guitar'. Find frequency of the letter 'm'
[EX A]: 1

[EX Q]: Sentence: 'five guys practicing surfboarding on the sandy beach'. Find frequency of the letter 'b'
[EX A]:
2