TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'

SOLUTION: 2

PROBLEM: Sentence: 'a person is water skiing and there are birds flying around above them'. Find frequency of the letter 'n'

SOLUTION: 5

PROBLEM: Sentence: 'a stone walled bathroom with a toilet and a sink'. Find frequency of the letter 'n'

SOLUTION:
3