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

Sentence: 'an airplane is being towed away from the jet bridge'. Find frequency of the letter 's'
1

Sentence: 'a surfer wipes out on a huge wave'. Find frequency of the letter 'a'
3

Sentence: 'a person riding their mountain bike off road'. Find frequency of the letter 'm'

1