#include <iostream>
#include <iomanip>
using namespace std;

int main() {
    double h,r;
    cin >> h >> r;
    long long h2=h*100,r2=r*100;
    long long ans1,ans2;
    ans1=6807*h2;
    ans2=7073*2*r2;
    cout << fixed << setprecision(10)<< -8.245+(double)ans1/100000+(double)ans2/100000*3.141592653589793238 << endl;
}