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

Ex Input:
Sentence: 'salad and vegetables with me on top of plate'. Find frequency of the letter 'o'

Ex Output:
3


Ex Input:
Sentence: 'the counter of a doctor's office, including a laptop, cotton swabs, and tongue depressors'. Find frequency of the letter 'g'

Ex Output:
2


Ex Input:
Sentence: 'some sheep walking in the middle of a road'. Find frequency of the letter 'h'

Ex Output:

2