TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a man in a sweatshirt is taking his own picture'. Find frequency of the letter 'u'

SOLUTION: 1

PROBLEM: Sentence: 'a flock of sheep grazing in a park'. Find frequency of the letter 'f'

SOLUTION: 2

PROBLEM: Sentence: 'a cute little dog holding onto a firsbee'. Find frequency of the letter 'l'

SOLUTION:
3