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 laying on a bed posing for a picture'. Find frequency of the letter 'i'

SOLUTION: 4

PROBLEM: Sentence: 'a doorway looking into a small bathroom with white toilet'. Find frequency of the letter 'r'

SOLUTION: 2

PROBLEM: Sentence: 'black motorcycle standing on display outside in the sun'. Find frequency of the letter 'n'

SOLUTION:
5