TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a train is sitting at a train station'. Find frequency of the letter 'r'

SOLUTION: 2

PROBLEM: Sentence: 'a bowl of vegetables in a soup like substance next to a spoon'. Find frequency of the letter 'a'

SOLUTION: 5

PROBLEM: Sentence: 'large commuter train parked on the track with no people around'. Find frequency of the letter 'r'

SOLUTION:
6