In this task, you need to count the number of times the given letter appears in the given sentence.
--------
Question: Sentence: 'the sun goes down over a bike tied to a bench at the beach'. Find frequency of the letter 't'

Answer: 5


Question: Sentence: 'a woman is looking at sheep off in a field'. Find frequency of the letter 'm'

Answer: 1


Question: Sentence: 'an old train is pulling into a train station'. Find frequency of the letter 'l'

Answer:
3