TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a double decker transit bus parks by a blue on the side of the street in front of a brick building in the city'. Find frequency of the letter 't'

SOLUTION: 9

PROBLEM: Sentence: 'an old woman is holding her cat in front of a camera'. Find frequency of the letter 'r'

SOLUTION: 3

PROBLEM: Sentence: 'a red, white, cream and tan colored traffic sign on the corner'. Find frequency of the letter 'd'

SOLUTION:
3