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

Ex Input:
Sentence: 'a piece of film shows two street signs crossing each other'. Find frequency of the letter 'f'

Ex Output:
2


Ex Input:
Sentence: 'a bedroom with a neatly made bed and a laptop'. Find frequency of the letter 'l'

Ex Output:
2


Ex Input:
Sentence: 'a woman walking with a man and holding an umbrella looks off to the side'. Find frequency of the letter 'd'

Ex Output:

3