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: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'
[EX A]: 5

[EX Q]: Sentence: 'a man in a sweatshirt is taking his own picture'. Find frequency of the letter 'u'
[EX A]:
1