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

Sentence: 'a man with glasses adjusting his tie in a mirror'. Find frequency of the letter 's'
5

Sentence: 'there is a stop sign that has a reflection in a puddle'. Find frequency of the letter 'e'
5

Sentence: 'a clock is illuminated against the dark sky'. Find frequency of the letter 't'

3