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

Q: Sentence: 'an area that has surrounded by a metal fence'. Find frequency of the letter 'o'

A: 1
****
Q: Sentence: 'a black bear sitting in the grass taking a rest'. Find frequency of the letter 'a'

A: 6
****
Q: Sentence: 'a baseball player is up to bat at a game'. Find frequency of the letter 'r'

A:
1
****