#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; cin>>r; printf("%.4f",4.0/3*3.1415926*r*r*r ); return 0; }