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 in costume talking on a cell phone'. Find frequency of the letter 'm'

SOLUTION: 2

PROBLEM: Sentence: 'a herd of zebra standing on top  of a grass covered field'. Find frequency of the letter 'e'

SOLUTION: 5

PROBLEM: Sentence: 'there is a male tennis player playing on the court'. Find frequency of the letter 'n'

SOLUTION:
4