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

Ex Input:
Sentence: 'a tall building with antenna stands before a jet flying in the background'. Find frequency of the letter 't'

Ex Output:
6


Ex Input:
Sentence: 'a castle like bed room that has the era of templar knight similarities'. Find frequency of the letter 'm'

Ex Output:
3


Ex Input:
Sentence: 'a glass table top with a computer on top of it'. Find frequency of the letter 'm'

Ex Output:

1