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

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 couple of items that are on the wall'. Find frequency of the letter 'm'

Ex Output:
1


Ex Input:
Sentence: 'a boat is docked in the water near a large house'. Find frequency of the letter 'l'

Ex Output:

1