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

Ex Input:
Sentence: 'four women around a man sitting in front of a cake'. Find frequency of the letter 'o'

Ex Output:
5


Ex Input:
Sentence: 'a bowl of vegetables in a soup like substance next to a spoon'. Find frequency of the letter 'a'

Ex Output:
5


Ex Input:
Sentence: 'a person with laptop and two cats'. Find frequency of the letter 'a'

Ex Output:

4