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

Q: Sentence: 'three young children playing with a ball in front of a huge bridge'. Find frequency of the letter 'e'

A: 5
****
Q: Sentence: 'a man opening up a package sitting on a couch'. Find frequency of the letter 'n'

A: 5
****
Q: Sentence: 'a group of people waiting to board the underground subway'. Find frequency of the letter 'i'

A:
2
****