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

Ex Input:
Sentence: 'a plastic tray that has different foods inside of it'. Find frequency of the letter 't'

Ex Output:
6


Ex Input:
Sentence: 'decorated baseball cake in a clear plastic box'. Find frequency of the letter 'k'

Ex Output:
1


Ex Input:
Sentence: 'two women smiling for a picture while on the ski slope'. Find frequency of the letter 'u'

Ex Output:

1