Problem K: Cylinder

Problem K: Cylinder

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 17  Solved: 7
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Description

Using a sheet of paper and scissors, you can cut out two faces to form a cylinder in the following way: 


Cut the paper horizontally (parallel to the shorter side) to get two rectangular parts. 

From the first part, cut out a circle of maximum radius. The circle will form the bottom of the cylinder. 

Roll the second part up in such a way that it has a perimeter of equal length with the circle's circumference, and attach one end of the roll to the circle. Note that the roll may have some overlapping parts in order to get the required length of the perimeter. 

Given the dimensions of the sheet of paper, can you calculate the biggest possible volume of a cylinder which can be constructed using the procedure described above? 

Input

The input consists of several test cases. Each test case consists of two numbers w and h (1 ≤ w ≤ h ≤ 100), which indicate the width and height of the sheet of paper. 

The last test case is followed by a line containing two zeros. 

Output

For each test case, print one line with the biggest possible volume of the cylinder. Round this number to 3 places after the decimal point. 

Sample Input

10 1010 5010 300 0

Sample Output

54.247785.398412.095

HINT

这一题的主要意思就是给你一张纸，让你剪成两半，一张留着做底一张留着做身，问这个圆筒最大的容积！

注意精度问题就可以了！不注意WA不知道原因

#include<stdio.h>#define PI 3.141592653589double area(double x,double y){//以x为园的周长double r,s,v;r=x/(PI*2);s=PI*r*r;v=s*(y-x/PI);return v; }int main(){double w,h,v1,v2,r,r1,s;while(scanf("%lf%lf",&w,&h)&&(w||h)){//x为圆的高r1=h/(PI+1)/2;if(r1>w/2){r=w/2;}else{r=r1;}s=PI*r*r;v1=s*w;v2=area(w,h);        if(v1>v2){printf("%.3lf\n",v1);}else{printf("%.3lf\n",v2);}}}