TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a table topped with a cupcake on a picture of a cupcake'. Find frequency of the letter 'o'

SOLUTION: 3

PROBLEM: Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'

SOLUTION: 2

PROBLEM: Sentence: 'there is a person standing on a blue towel'. Find frequency of the letter 'n'

SOLUTION:
4