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

Sentence: 'a man that is on his cell phone'. Find frequency of the letter 's'
2

Sentence: 'a tower with some bright lights and clocks on it'. Find frequency of the letter 'h'
3

Sentence: 'a small plane is parked on top of a tree'. Find frequency of the letter 'k'

1