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

Sentence: 'the large modern train is on the train track'. Find frequency of the letter 'm'
1

Sentence: 'a baby elephant walks beside an adult elephant along a post and cable'. Find frequency of the letter 'l'
6

Sentence: 'a man sitting on a bus using a smart phone'. Find frequency of the letter 's'

4