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

Ex Input:
Sentence: 'a family sitting at a table in a restaurant looking at their phones'. Find frequency of the letter 't'

Ex Output:
8

Ex Input:
Sentence: 'bathroom scene with a black cat going behind the door'. Find frequency of the letter 'e'

Ex Output:
4

Ex Input:
Sentence: 'a man holding a remote controller in front of a building'. Find frequency of the letter 'l'

Ex Output:
4