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: 'a black bear sitting in the grass taking a rest'. Find frequency of the letter 'a'

SOLUTION: 6

PROBLEM: Sentence: 'kites being flown along the coast line in the morning'. Find frequency of the letter 's'

SOLUTION:
2