#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;
 
#include<bits/stdc++.h>
using namespace std;

int main(){
  double h,r;
  cin>>h>>r;
  
  double v=30574.154032453271139*h*r*r/912.7/548.36/548.36;
  cout<<fixed<<setprecision(10)<<v<<endl;
  
    
  return 0;
}