TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'man in a sleeping bag on the floor using a laptop computer'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'a man and several white red and blue airplanes'. Find frequency of the letter 'u'

SOLUTION: 1

PROBLEM: Sentence: 'a large tub in a bathroom next to a window'. Find frequency of the letter 'e'

SOLUTION:
2