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

Q: Sentence: 'a man using a video game controller in a room'. Find frequency of the letter 'n'

A: 4
****
Q: Sentence: 'the little girl is flying her kite in the field'. Find frequency of the letter 'i'

A: 7
****
Q: Sentence: 'a person rides a surfboard while being pulled by a rope'. Find frequency of the letter 'a'

A:
4
****