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

Sentence: 'a jet that is flying in the sky with a banner behind it'. Find frequency of the letter 'r'
1

Sentence: 'one man grabbing another at a table while laughing'. Find frequency of the letter 'n'
5

Sentence: 'a person "jumps" over a snow-covered mountain on skis'. Find frequency of the letter 'd'

1