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

Ex Input:
Sentence: 'a knife a cutting board some bananas and a toaster'. Find frequency of the letter 'i'

Ex Output:
2


Ex Input:
Sentence: 'a boy that is sitting at a table with pizza'. Find frequency of the letter 's'

Ex Output:
2


Ex Input:
Sentence: 'a close up of a bowl of different fruits'. Find frequency of the letter 'l'

Ex Output:

2