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

Ex Input:
Sentence: 'a bus is stopped in front of a graphic statue'. Find frequency of the letter 'e'

Ex Output:
2


Ex Input:
Sentence: 'a group of people standing around a table filled with assorted electronic devices'. Find frequency of the letter 'w'

Ex Output:
1


Ex Input:
Sentence: 'the street lights are shining bright on the dark street'. Find frequency of the letter 'e'

Ex Output:

7