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

Sentence: 'a mixed bouquet of flowers in a glass vase set before a window'. Find frequency of the letter 'w'
3

Sentence: 'an old woman is holding her cat in front of a camera'. Find frequency of the letter 'r'
3

Sentence: 'two guys are playing the wii, while the folks on the table look on'. Find frequency of the letter 't'
5