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

Sentence: 'a log in the water with three birds perched on it'. Find frequency of the letter 'r'
4

Sentence: 'four women around a man sitting in front of a cake'. Find frequency of the letter 'o'
5

Sentence: 'a kitty playing with a wii remote on the couch'. Find frequency of the letter 'o'

3