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

Sentence: 'a row of vintage cars in a grassy field'. Find frequency of the letter 'v'
1

Sentence: 'a family out snow skiing on a blustery day'. Find frequency of the letter 'i'
3

Sentence: 'a person's feet is standing on a skateboard which is on an electronic circuit board'. Find frequency of the letter 'n'

7