TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a microwave oven with a yellow note on the door'. Find frequency of the letter 'w'

SOLUTION: 3

PROBLEM: Sentence: 'a man flying through the air on a bicycle'. Find frequency of the letter 'u'

SOLUTION: 1

PROBLEM: Sentence: 'an outdoor market selling a variety of fruits'. Find frequency of the letter 'o'

SOLUTION:
4