TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a boy that is sitting at a table with pizza'. Find frequency of the letter 's'

SOLUTION: 2

PROBLEM: Sentence: 'a glass a rope and a pair of scissors'. Find frequency of the letter 's'

SOLUTION: 6

PROBLEM: Sentence: 'the monument in front of the fence has signs in a foreign language'. Find frequency of the letter 'a'

SOLUTION:
4