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 riding a white surfboard on a large wave'. Find frequency of the letter 'a'

SOLUTION: 7

PROBLEM: Sentence: 'two giraffes, one standing and one laying down'. Find frequency of the letter 'g'

SOLUTION: 3

PROBLEM: Sentence: 'a little boy that has a toothbrush in his mouth'. Find frequency of the letter 'r'

SOLUTION:
1