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, one standing and one laying down'. Find frequency of the letter 'g'

SOLUTION: 3

PROBLEM: Sentence: 'a glass a rope and a pair of scissors'. Find frequency of the letter 's'

SOLUTION: 6

PROBLEM: Sentence: 'this is a cat sitting on a bed'. Find frequency of the letter 'i'

SOLUTION:
4