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

Sentence: 'young girl playing with refrigerator magnet while kneeling on floor'. Find frequency of the letter 'n'
6

Sentence: 'a man walking a large elephant down a dirt road'. Find frequency of the letter 'g'
2

Sentence: 'a double decker bus is sitting in traffic in england'. Find frequency of the letter 'n'

5