// 8.245 + 6.807 * H + 7.073 * FFC
#include <bits/stdc++.h>
using namespace std;

int main(){
    double h, f; cin >> h >> f;
    cout << fixed << setprecision(12) << (-8.245 + 6.807 * h + 7.073 * f * 2.0 * 3.14159265358979) << endl;
}