#include "stdio.h"#define PI 3.1415927int main(void){	double r;	double v;		while(scanf("%lf", &r) != EOF){		if(r < 0.000){			break;		}				v = (double)4/3 * PI * r * r * r;		printf("%.3lf\n", v);				v = 0.000;	} 		return 0;}