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

Ex Input:
Sentence: 'a man sitting in front of a laptop computer next to a child'. Find frequency of the letter 'e'

Ex Output:
2


Ex Input:
Sentence: 'people fishing and enlarge mountainlake with trees lining the shoreline'. Find frequency of the letter 't'

Ex Output:
4


Ex Input:
Sentence: 'four older ladies sitting by a christmas tree'. Find frequency of the letter 'e'

Ex Output:

4