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

[EX Q]: Sentence: 'a small boat and a large boat on a river near a city'. Find frequency of the letter 'a'
[EX A]: 10

[EX Q]: Sentence: 'two baseball players high five each other during a game'. Find frequency of the letter 'y'
[EX A]: 1

[EX Q]: Sentence: 'the teddy bear is posed with a note and a guitar'. Find frequency of the letter 't'
[EX A]:
5