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

Ex Input:
Sentence: 'a row of vintage cars in a grassy field'. Find frequency of the letter 'v'

Ex Output:
1


Ex Input:
Sentence: 'a woman holds a wine glass upside down while wearing rabbit ears and staring at a bottle of wine'. Find frequency of the letter 'a'

Ex Output:
11


Ex Input:
Sentence: 'a glass sits on top of some fruits set on a table'. Find frequency of the letter 'a'

Ex Output:

4