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

Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'
2

Sentence: 'the skateboarder has on red and black sneakers and is riding a skateboard'. Find frequency of the letter 'g'
1

Sentence: 'a wooden cutting board topped with a cake and cookies next to donuts'. Find frequency of the letter 'p'
2