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

Sentence: 'a baseball themed birthday cake is on a serving tray'. Find frequency of the letter 'g'
1

Sentence: 'group of snowboarders on a snowy trail overlooking a mountain'. Find frequency of the letter 'r'
5

Sentence: 'a stop sign topped by two green street signs'. Find frequency of the letter 'e'

5