TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a variety of a different type of vegetables'. Find frequency of the letter 't'

SOLUTION: 4

PROBLEM: Sentence: 'vanity sitting atop a base with two doors and a mirror overhead'. Find frequency of the letter 'n'

SOLUTION: 3

PROBLEM: Sentence: 'the police officer is driving his motorcycle threw the city streets'. Find frequency of the letter 's'

SOLUTION:
4