TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a guy surfs a wave with his surfboard'. Find frequency of the letter 's'

SOLUTION: 4

PROBLEM: Sentence: 'a man with a large grey and black beard and glasses and a tie'. Find frequency of the letter 'e'

SOLUTION: 5

PROBLEM: Sentence: 'a young man prepares to swing a bat at home plate'. Find frequency of the letter 't'

SOLUTION:
4