你想当2^n元富翁吗? So you want to be a 2n-aire?

题目描述

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=21&page=show_problem&problem=1841 [PDF](https://uva.onlinejudge.org/external/109/p10900.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10900/f1ba9ec1e6c53efbf6006769c69b3fb5b41b5910.png)

输入输出格式

输入格式


![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10900/ec92d9f06c2ad4e9f3aefdf9f4e143269d17af67.png)

输出格式


![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10900/2c15f0c9f6a45695ac1e17e8b075318a280669c6.png)

输入输出样例

输入样例 #1

1 0.5
1 0.3
2 0.6
24 0.25
0 0

输出样例 #1

1.500
1.357
2.560
230.138