概率,谁能告诉我这个怎么求概率Time goes by.And at the exact days that Bob has counted out atprobability II,Alice is touched by Bob and she is willing to be Bob's girlfriend.But before this,Alice decided to test the Bob's ability.Alice al

概率,谁能告诉我这个怎么求概率Time goes by.And at the exact days that Bob has counted out atprobability II,Alice is touched by Bob and she is willing to be Bob's girlfriend.But before this,Alice decided to test the Bob's ability.Alice al
概率,谁能告诉我这个怎么求概率
Time goes by.And at the exact days that Bob has counted out atprobability II,Alice is touched by Bob and she is willing to be Bob's girlfriend.But before this,Alice decided to test the Bob's ability.Alice also likes probability very much.So she asked Bob a probability question:
There areNballs in a bag.They are in red color or blue.But you don't know the exact the sum of red balls is.So you can assume the sum of the red ballsSr( 0 ≤Sr≤N) probabilitytis equal.You getmballs from the bag,and you find in themballs there areqred balls andm-qblue balls.So what is the expection of probability that if you then (after get out themballs) get another ball in the bag and find the ball is blue?
Bob,as we know,is good at probability.So he solves the problem without thinking even just after the Alice has asked him.Alice believes Bob is a genius.They are together!
What a happy ending!
What importance the math is!Can you solve Alice's problem?
Input
There are several test cases in the input file.Each test case contains only one line with three integersN,mandq( 2 ≤N≤ 10000,0 ≤m≤N-1,0 ≤q≤m).
Output
For each test case,output the exception of probability in a single line.The number should be rounded to four decimal places.
Sample Input
3 0 0
Sample output
0.5000

概率,谁能告诉我这个怎么求概率Time goes by.And at the exact days that Bob has counted out atprobability II,Alice is touched by Bob and she is willing to be Bob's girlfriend.But before this,Alice decided to test the Bob's ability.Alice al
时间流逝,某一天,Bob接触到了概率II,Alice被Bob感动了,愿意做他的女朋友,但是首先,她想先考验一下Bob的能力.因为Alice也很喜欢概率,所以她问Bob一个关于概率的问题：
袋子中有N个小球（红色或者蓝色）,但是你不知道每种颜色具体的小球个数.所以,你可以假设红色的小球的个数为Sr（0