TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a couple of boys in a field playing baseball'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'there are two men sitting on a couch playing video games'. Find frequency of the letter 'v'

SOLUTION: 1

PROBLEM: Sentence: 'a variety of stuffed toys assembled on a pile of leaves'. Find frequency of the letter 'l'

SOLUTION:
3