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

Ex Input:
Sentence: 'a kitchen with hanging lights, an island with sink and bar stools, a refrigerator, small pantry door, wooden cabinets and shiny wood floor'. Find frequency of the letter 'n'

Ex Output:
12


Ex Input:
Sentence: 'a teddy bear is sitting on a heart shaped patio chair outside'. Find frequency of the letter 'i'

Ex Output:
6


Ex Input:
Sentence: 'a bearded man in a hat sitting on a bench with an obama placard'. Find frequency of the letter 'g'

Ex Output:

1


