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

Sentence: 'an airplane is being towed away from the jet bridge'. Find frequency of the letter 's'
1

Sentence: 'a boy that is sitting at a table with pizza'. Find frequency of the letter 's'
2

Sentence: 'a young girl is sitting in front of a birthday cake'. Find frequency of the letter 'y'

2