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

Ex Input:
Sentence: 'the ingredients are ready on the wooden table'. Find frequency of the letter 'w'

Ex Output:
1


Ex Input:
Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'

Ex Output:
4


Ex Input:
Sentence: 'a couple of bikes are parked outside together'. Find frequency of the letter 'd'

Ex Output:

2