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

Sentence: 'a teddy bear is sitting on a heart shaped patio chair outside'. Find frequency of the letter 'i'
6

Sentence: 'four men standing around two pizzas in a conference room'. Find frequency of the letter 't'
2

Sentence: 'a child in a red coat walking towards a red boat'. Find frequency of the letter 'a'
7