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

Input: Consider Input: Sentence: 'a man in a sweatshirt is taking his own picture'. Find frequency of the letter 'u'

Output: 1


Input: Consider Input: Sentence: 'a man in a black wet suit rides an orange surfboard on the water'. Find frequency of the letter 'o'

Output: 3


Input: Consider Input: Sentence: 'some people walking past a tourist bus toward a castle'. Find frequency of the letter 'l'


Output: 3