TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'people playing wii bowling in a modern library'. Find frequency of the letter 'o'

SOLUTION: 3

PROBLEM: Sentence: 'a couple of boys in a field playing baseball'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'a vase with red and white flowers outside on a sunny day'. Find frequency of the letter 'u'

SOLUTION:
2