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

Ex Input:
Sentence: 'two laptop computers sitting on top of a white table'. Find frequency of the letter 'f'

Ex Output:
1

Ex Input:
Sentence: 'a truck is parked in front of a store'. Find frequency of the letter 't'

Ex Output:
3

Ex Input:
Sentence: 'a tv on top of a wooden dresser next to a desk'. Find frequency of the letter 'k'

Ex Output:
1