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

Sentence: 'some people sitting on surfboards in the water'. Find frequency of the letter 't'
4

Sentence: 'two elephants walking on cement next to wall'. Find frequency of the letter 'n'
5

Sentence: 'an elephant lifting up a hate with it's trunk'. Find frequency of the letter 'i'

4