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

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: 'two young ladies that are dancing in the room together'. Find frequency of the letter 'a'

Ex Output:
4


Ex Input:
Sentence: 'a man standing in front of microphones'. Find frequency of the letter 'f'

Ex Output:

2