九度Online Judge

OJ新增积分机制,如有任何问题或者建议,请发帖到九度论坛OJ意见反馈版,祝大家一切顺利!
亲,九度OJ官方微博开通了,欢迎你来粉!微博地址:weibo.com/jobdu

 题目1433-九度Online Judge,用代码记录你的成长之路!

题目1433:FatMouse

时间限制:1 秒

内存限制:128 兆

特殊判题:

提交:5229

解决:2331

题目描述:

FatMouse prepared M pounds of cat food, ready to trade with the cats guarding the warehouse containing his favorite food, JavaBean.
The warehouse has N rooms. The i-th room contains J[i] pounds of JavaBeans and requires F[i] pounds of cat food. FatMouse does not have to trade for all the JavaBeans in the room, instead, he may get J[i]* a% pounds of JavaBeans if he pays F[i]* a% pounds of cat food. Here a is a real number. Now he is assigning this homework to you: tell him the maximum amount of JavaBeans he can obtain.

输入:

The input consists of multiple test cases. Each test case begins with a line containing two non-negative integers M and N. Then N lines follow, each contains two non-negative integers J[i] and F[i] respectively. The last test case is followed by two -1's. All integers are not greater than 1000.

输出:

For each test case, print in a single line a real number accurate up to 3 decimal places, which is the maximum amount of JavaBeans that FatMouse can obtain.

样例输入:
5 3
7 2
4 3
5 2
20 3
25 18
24 15
15 10
-1 -1
样例输出:
13.333
31.500