#include <bits/stdc++.h>
using namespace std;

struct iofast_t {
    iofast_t() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr); cout.tie(nullptr);
    }
} iofast;

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return std::vector(arg, init);
    else return std::vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

template <typename T, typename Compare = less<T>>
T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); }
template <typename T, typename Compare = less<T>>
T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); }

#include <boost/multiprecision/cpp_dec_float.hpp>
using bfloat = boost::multiprecision::cpp_dec_float_100;

int main() {
    bfloat h, r; cin >> h >> r;
    cout << fixed << setprecision(15) << (bfloat("-8.245") + bfloat("6.807") * h + bfloat("7.073") * 2 * r * bfloat("3.141592653589793238462643383279502884")) << endl;
}