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

[EX Q]: Sentence: 'a family out snow skiing on a blustery day'. Find frequency of the letter 'i'
[EX A]: 3

[EX Q]: Sentence: 'a railroad train pulling up to the train platform'. Find frequency of the letter 'o'
[EX A]: 3

[EX Q]: Sentence: 'the black cow with white spots is lying on the hay beside an identical calf'. Find frequency of the letter 'e'
[EX A]:
6