#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
static const double pai=3.14159265358979;
int main(){
  double s,a,b;
  cin>>a>>b;
  
  s = -8.245 + 6.807 * a + 7.073 * b*2*pai;
  cout<<setprecision(18)<<s<<endl;

  return 0;
}