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

Sentence: 'pedestrian in stripe clothing standing on street corner'. Find frequency of the letter 's'
4

Sentence: 'a person dressed all in black snowboarding down a slope'. Find frequency of the letter 'e'
4

Sentence: 'the attendant is straightening a bed while someone lies in it'. Find frequency of the letter 'n'
6