TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a person is performing a stunt on a snowboard'. Find frequency of the letter 'p'

SOLUTION: 2

PROBLEM: Sentence: 'a sheep in a field in front of other sheep'. Find frequency of the letter 'f'

SOLUTION: 3

PROBLEM: Sentence: 'the long haired horse is enjoying the grass under the fence'. Find frequency of the letter 'd'

SOLUTION:
2