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

Sentence: 'a woman standing in front of a bathroom sink in front of a mirror'. Find frequency of the letter 'o'
8

Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'
2

Sentence: 'an old photo of a group of female tennis players with rackets'. Find frequency of the letter 'e'

5