TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a group of cows that are standing in the grass'. Find frequency of the letter 'g'

SOLUTION: 3

PROBLEM: Sentence: 'a fluffy white car looking in a mirror'. Find frequency of the letter 'k'

SOLUTION: 1

PROBLEM: Sentence: 'a female tennis player on the court at a competitive match'. Find frequency of the letter 'c'

SOLUTION:
3