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

Sentence: 'a social occasion of people are uncovered before the open day'. Find frequency of the letter 'c'
4

Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'
4

Sentence: 'a kitchen that has a grey tile floor with granite counter top and a silver stove and a silver refrigerator'. Find frequency of the letter 'a'

10