TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'oranges are sitting in a bowl on a table'. Find frequency of the letter 'a'

SOLUTION: 5

PROBLEM: Sentence: 'a group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'

SOLUTION: 3

PROBLEM: Sentence: 'white passenger train sitting still at a train station'. Find frequency of the letter 't'

SOLUTION:
9