shunfurh 于 2017.07.17 15:48 提问
Mickey is interested in probability recently. One day , he played a game which is about probability with mini.First mickey gives a letter and a word to mini.Then mini calculate the probability that the letter appears in the word.For example,give you the letter "a" and the word "apple". the probability of this case is 0.20000.
The input contains several test cases. Each test case consists of a letter and a word.The length of the word is no longer than 200.
For each test case, print the probability rounded to five digits after the decimal point.