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

Ex Input:
Sentence: 'a desk covered in notepads, a laptop and other devices'. Find frequency of the letter 'c'

Ex Output:
2


Ex Input:
Sentence: 'a young elephant is touching a bigger elephant with its trunk'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'cat looking around television with dog on it'. Find frequency of the letter 'g'

Ex Output:

2