TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a girl sits on a surfboard and smiles'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'a group of people having dinner and drinking wine'. Find frequency of the letter 'r'

SOLUTION: 3

PROBLEM: Sentence: 'an office table holding a monitor and keyboard in a room'. Find frequency of the letter 'a'

SOLUTION:
6