TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a small boat and a large boat on a river near a city'. Find frequency of the letter 'a'

SOLUTION: 10

PROBLEM: Sentence: 'two zebras standing around while a third zebra drinks from a pond'. Find frequency of the letter 's'

SOLUTION: 3

PROBLEM: Sentence: 'a woman holding a nintendo wii game controller'. Find frequency of the letter 'g'

SOLUTION:
2