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

Ex Input:
Sentence: 'a plane with smoke coming from the tips of both wings'. Find frequency of the letter 'c'

Ex Output:
1


Ex Input:
Sentence: 'a pizza pie sitting on a wooden table with tongs'. Find frequency of the letter 't'

Ex Output:
5


Ex Input:
Sentence: 'an odd looking black duck with a colorful beak'. Find frequency of the letter 'l'

Ex Output:

4