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

[EX Q]: Sentence: 'a piece of bread stuffed with meat and vegetables'. Find frequency of the letter 's'
[EX A]: 2

[EX Q]: Sentence: 'there is an old stove with old pots on the burners'. Find frequency of the letter 't'
[EX A]: 5

[EX Q]: Sentence: 'two young elephants walk on an open field'. Find frequency of the letter 'o'
[EX A]:
4