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

Sentence: 'a woman is playing an interactive video game'. Find frequency of the letter 't'
2

Sentence: 'an elephant has taken a man's hat in its trunk'. Find frequency of the letter 'p'
1

Sentence: 'a cardboard garage sale sign stapled to a post'. Find frequency of the letter 'o'

3