#include using namespace std; using ll = long long int; using ld = long double; #define pow(n,m) powl(n,m); #define sqrt(n) sqrtl(n); const ll MAX = 5000000000000000000; const ll MOD = 1000000007; //998244353; void randinit(){srand((unsigned)time(NULL));} int main(){ ld H,R; cin >> H >> R; cout << -8.245 + 6.807 * H + 7.73 * R * 2 * 3.141592653589793238 << endl; }