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

Sentence: 'a girl that has a kite in the air'. Find frequency of the letter 'r'
2

Sentence: 'a man standing on a surf board in the ocean'. Find frequency of the letter 'f'
1

Sentence: 'the baby elephant is taking a cooling mud bath'. Find frequency of the letter 'h'

3