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

Ex Input:
Sentence: 'a bird is perched on a container in a person's hand'. Find frequency of the letter 'c'

Ex Output:
2


Ex Input:
Sentence: 'pizza with different vegetables sitting on top of a wooden slab'. Find frequency of the letter 'o'

Ex Output:
5


Ex Input:
Sentence: 'a wet dog on a surfboard and wearing pink'. Find frequency of the letter 'p'

Ex Output:

1