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

Ex Input:
Sentence: 'man sitting on the side of a van playing the guitar'. Find frequency of the letter 'm'

Ex Output:
1


Ex Input:
Sentence: 'there are two men sitting on a couch playing video games'. Find frequency of the letter 'v'

Ex Output:
1


Ex Input:
Sentence: 'two traffic lights hang front a power line'. Find frequency of the letter 'h'

Ex Output:

2