题目：​​http://acm.hdu.edu.cn/showproblem.php?pid=2002​​

#include <stdio.h>
 #define PI 3.1415927
 int main()
 {
     double r;
     while(scanf("%lf",&r)!=EOF)
         printf("%.3lf\n",4/3.0*PI*r*r*r);
     return 0;
 }