FatMouse' Trade

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 33038 Accepted Submission(s): 10693

Problem Description

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.

Input

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.

Output

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.

Sample Input

5 3

7 2

4 3

5 2

20 3

25 18

24 15

15 10

-1 -1

Sample Output

13.333

31.500

Author

CHEN, Yue

Source

ZJCPC2004

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1 #include
      
         2 #include
       
          3 #include
        
           4 #include
         
            5 #include
          
             6 using namespace std;  7      8 struct node  9 { 10     int ja,va; 11     double sor; 12 }edge[10001]; 13     14 bool cmp(node a,node b) 15 { 16     return a.sor
           
            edge[i].va) 38 { 39 sum+=edge[i].ja; 40 m-=edge[i].va; 41 } 42 else43 { 44 sum+=m*1.0/edge[i].va*edge[i].ja; 45 break; 46 } 47 } 48 printf("%0.3lf\n",sum); 49 } 50 return 0; 51 }