TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a bird outside standing on a table looking up'. Find frequency of the letter 'b'

SOLUTION: 2

PROBLEM: Sentence: 'a white toilet sitting next to a toilet paper roller'. Find frequency of the letter 'o'

SOLUTION: 4

PROBLEM: Sentence: 'this parking meter at the curb has numbers on it'. Find frequency of the letter 't'

SOLUTION:
5