TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a truck is parked in front of a store'. Find frequency of the letter 't'

SOLUTION: 3

PROBLEM: Sentence: 'a white police vehicle parked on a paved street'. Find frequency of the letter 'a'

SOLUTION: 4

PROBLEM: Sentence: 'there is a plane in the water near the bridge'. Find frequency of the letter 'i'

SOLUTION:
3