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

[EX Q]: Sentence: 'soccer players on opposite teams fight for control over a ball'. Find frequency of the letter 't'
[EX A]: 4

[EX Q]: Sentence: 'a train is sitting at a train station'. Find frequency of the letter 'r'
[EX A]: 2

[EX Q]: Sentence: 'top picture is some fancy hors d'oeuvre and the bottom picture is a cheese chili hotdog with potato chips'. Find frequency of the letter 'e'
[EX A]:
9