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

Sentence: 'old double decker bus parked in a lot'. Find frequency of the letter 't'
1

Sentence: 'a crowd of fans watch soccer players from stadium seating'. Find frequency of the letter 'f'
3

Sentence: 'a group of people in the water on surfboards'. Find frequency of the letter 'r'

4