TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'baseball player reaching back as he's about to throw the ball'. Find frequency of the letter 'e'

SOLUTION: 5

PROBLEM: Sentence: 'the wooden kitchen has a small child's plastic table in it'. Find frequency of the letter 'n'

SOLUTION: 3

PROBLEM: Sentence: 'a double decker bus is sitting in a lane in europe'. Find frequency of the letter 'n'

SOLUTION:
4