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

Sentence: 'a photo of a couple of people at a convention'. Find frequency of the letter 'v'
1

Sentence: 'a bedroom with a neatly made bed and a laptop'. Find frequency of the letter 'l'
2

Sentence: 'the control room for a train that is still on the tracks'. Find frequency of the letter 'c'

2