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

Sentence: 'man riding a skate board down the little board way'. Find frequency of the letter 'k'
1

Sentence: 'a dog has found a rather large stick for playing fetch'. Find frequency of the letter 't'
3

Sentence: 'a hummingbird looking at a little bird feeder'. Find frequency of the letter 'n'

2