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

Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'
4

Sentence: 'a woman walking with a child that is in a wheelchair'. Find frequency of the letter 'k'
1

Sentence: 'young woman on body board at water slide'. Find frequency of the letter 'u'

1