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

Ex Input:
Sentence: 'decorated baseball cake in a clear plastic box'. Find frequency of the letter 'k'

Ex Output:
1


Ex Input:
Sentence: 'a batter, catcher and umpire waiting for the pitch and a major league baseball game'. Find frequency of the letter 'c'

Ex Output:
3


Ex Input:
Sentence: 'a bathroom with several towels and a pink wastebasket'. Find frequency of the letter 'w'

Ex Output:

3