In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'a construction sign is displayed on a street'. Find frequency of the letter 'i'
4

Sentence: 'one man grabbing another at a table while laughing'. Find frequency of the letter 'n'
5

Sentence: 'someone has sliced a lot of apples for a special dessert'. Find frequency of the letter 'l'

4