#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ double r,s; scanf("%lf",&r); s=4.0/3*3.1415926*r*r*r; printf("%.4lf\n",s); return 0; }