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

Ex Input:
Sentence: 'man in a radio studio wearing a suit in front of a microphone'. Find frequency of the letter 't'

Ex Output:
3


Ex Input:
Sentence: 'a large group of motorcycles parked along a street'. Find frequency of the letter 'a'

Ex Output:
5


Ex Input:
Sentence: 'tower clock designed with two western shooters for entertainment display'. Find frequency of the letter 'h'

Ex Output:

2