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

Ex Input:
Sentence: 'a blue bowl holding mashed bananas and oatmeal with a bottle of sugar and cinnamon sitting beside it'. Find frequency of the letter 'g'

Ex Output:
3


Ex Input:
Sentence: 'a guy riding a bike close to a car in the street'. Find frequency of the letter 'i'

Ex Output:
4


Ex Input:
Sentence: 'a large plane is pointed upward after take off'. Find frequency of the letter 'r'

Ex Output:

3