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

Ex Input:
Sentence: 'a few men walking through a market place'. Find frequency of the letter 'f'

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 cow grazing in a meadow with mountains behind it'. Find frequency of the letter 'i'

Ex Output:

6