TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a group of people standing on grass with a train in the background'. Find frequency of the letter 'n'

SOLUTION: 6

PROBLEM: Sentence: 'an orange cat sitting on the ground next to a purse'. Find frequency of the letter 's'

SOLUTION: 2

PROBLEM: Sentence: 'a very cute giraffe standing by some bushes'. Find frequency of the letter 'h'

SOLUTION:
1