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

Sentence: 'cooked fish and green broccoli share a single white plate'. Find frequency of the letter 'c'
3

Sentence: 'a train station with a train pulling into the platform'. Find frequency of the letter 'i'
6

Sentence: 'people in the street dancing with people watching'. Find frequency of the letter 'a'

2