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

Sentence: 'a double parking meter is decorated with a picture of a girl with wings on her feet'. Find frequency of the letter 'r'
6

Sentence: 'the street sign is next to a curved road'. Find frequency of the letter 's'
3

Sentence: 'four horses and a couple at a beach'. Find frequency of the letter 'u'

2