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

Sentence: 'a woman is taking a sip of a drink from a glass'. Find frequency of the letter 'i'
4

Sentence: 'a bunch of green bananas is hanging on a tree'. Find frequency of the letter 'n'
7

Sentence: 'two men in suits pose next to each other'. Find frequency of the letter 'n'
3