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

[Q]: Sentence: 'a woman sitting in front of a giant slice of cheese pizza'. Find frequency of the letter 'e'
[A]: 4


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


[Q]: Sentence: 'a guy standing by a narrow road with a big blue bus'. Find frequency of the letter 'u'
[A]:
3