#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define _overload3(_1,_2,_3,name,...) name #define _rep(i,n) repi(i,0,n) #define repi(i,a,b) for(ll i=a;i=b;--i) #define rrep(...) _overload3(__VA_ARGS__,rrepi,_rrep,)(__VA_ARGS__) #define all(x) (x).begin(),(x).end() #define PRINT(V) cout << V << "\n" #define SORT(V) sort((V).begin(),(V).end()) #define RSORT(V) sort((V).rbegin(), (V).rend()) using namespace std; using ll = long long; templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b void cins(itr first,itr last){ for (auto i = first;i != last;i++){ cin >> (*i); } } template void array_output(itr start,itr goal){ string ans = "",k = " "; for (auto i = start;i != goal;i++) ans += to_string(*i)+k; if (!ans.empty()) ans.pop_back(); PRINT(ans); } ll gcd(ll a, ll b) { return a ? gcd(b%a,a) : b; } const ll INF = 1e16; const ll MOD = 1000000007; const ll MOD2 = 998244353; const ll MOD3 = 1e6; const ll EPS = 1e-10; int sgn(const double a){ return (a < -EPS ? -1 : (a > EPS ? +1 : 0)); } typedef pair pi; typedef pair P; typedef tuple tri; typedef pair point; typedef complex Point; typedef string::const_iterator State; const ll MAX = 125000; constexpr ll nx[4] = {-1,0,1,0}; constexpr ll ny[4] = {0,1,0,-1}; int main(){ /* ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); */ double h,r; cin >> h >> r; double pi = 3.14159265358979323846; double ans = -8.245+6.807*h+7.073*r*2*pi; printf("%.20lf\n",ans); }