TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a man standing on a tennis court holding a racquet'. Find frequency of the letter 's'

SOLUTION: 2

PROBLEM: Sentence: 'two people and two children walking in a building'. Find frequency of the letter 'd'

SOLUTION: 3

PROBLEM: Sentence: 'a tennis player wearing all white clothes prepares to hit a tennis ball'. Find frequency of the letter 'b'

SOLUTION:
1