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

Ex Input:
Sentence: 'a group of men standing around a table cutting a cake'. Find frequency of the letter 'g'

Ex Output:
3


Ex Input:
Sentence: 'a man swinging a bat while playing baseball'. Find frequency of the letter 'm'

Ex Output:
1


Ex Input:
Sentence: 'a man doing a trick on a skateboard going down a hill'. Find frequency of the letter 'g'

Ex Output:

3