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

Ex Input:
Sentence: 'the man is holding a plastic sled with snow in it next to a child'. Find frequency of the letter 'g'

Ex Output:
1


Ex Input:
Sentence: 'pedestrian in stripe clothing standing on street corner'. Find frequency of the letter 's'

Ex Output:
4


Ex Input:
Sentence: 'smoothies in plastic cups lined up in a glass container and a black crate full of oranges, bananas and pineapple'. Find frequency of the letter 'd'

Ex Output:

3