#include using ll = long long; using uint = unsigned int; using ull = unsigned long long; using ld = long double; template using max_heap = std::priority_queue; template using min_heap = std::priority_queue, std::greater>; constexpr int popcount(const ull v) { return v ? __builtin_popcountll(v) : 0; } constexpr int log2p1(const ull v) { return v ? 64 - __builtin_clzll(v) : 0; } constexpr int lsbp1(const ull v) { return __builtin_ffsll(v); } constexpr int clog(const ull v) { return v ? log2p1(v - 1) : 0; } constexpr ull ceil2(const ull v) { return 1ULL << clog(v); } constexpr ull floor2(const ull v) { return v ? (1ULL << (log2p1(v) - 1)) : 0ULL; } constexpr bool btest(const ull mask, const int ind) { return (mask >> ind) & 1ULL; } template void bset(T& mask, const int ind) { mask |= ((T)1 << ind); } template void breset(T& mask, const int ind) { mask &= ~((T)1 << ind); } template void bflip(T& mask, const int ind) { mask ^= ((T)1 << ind); } template void bset(T& mask, const int ind, const bool b) { (b ? bset(mask, ind) : breset(mask, ind)); } template bool chmin(T& a, const T& b) { return (a > b ? a = b, true : false); } template bool chmax(T& a, const T& b) { return (a < b ? a = b, true : false); } template constexpr T inf_v = std::numeric_limits::max() / 4; template constexpr Real pi_v = Real{3.141592653589793238462643383279502884}; template constexpr T TEN(const int n) { return n == 0 ? T{1} : TEN(n - 1) * T{10}; } template struct fix : F { fix(F&& f) : F{std::forward(f)} {} template auto operator()(Args&&... args) const { return F::operator()(*this, std::forward(args)...); } }; template auto nd_array(int const (&szs)[n], const T x = T{}) { if constexpr (i == n) { return x; } else { return std::vector(szs[i], nd_array(szs, x)); } } class printer { public: printer(std::ostream& os_ = std::cout) : m_os{os_} { m_os << std::fixed << std::setprecision(15); } template int ln(const Args&... args) { return dump(args...), m_os << '\n', 0; } template int el(const Args&... args) { return dump(args...), m_os << std::endl, 0; } template int fmt(const std::string& s, const Args&... args) { return rec(s, 0, args...); } private: template int dump(const T& v) { return m_os << v, 0; } template int dump(const std::vector& vs) { for (int i = 0; i < (int)vs.size(); i++) { m_os << (i ? " " : ""), dump(vs[i]); } return 0; } template int dump(const std::vector>& vss) { for (int i = 0; i < (int)vss.size(); i++) { m_os << (0 <= i or i + 1 < (int)vss.size() ? "\n" : ""), dump(vss[i]); } return 0; } template int dump(const T& v, const Args&... args) { return dump(v), m_os << ' ', dump(args...), 0; } int rec(const std::string& s, int index) { return m_os << s.substr(index, s.size()), 0; } template int rec(const std::string& s, int index, const T& v, const Args&... args) { return index == s.size() ? 0 : s[index] == '%' ? (tdump(v), rec(s, index + 1, args...)) : (m_os << s[index], rec(s, index + 1, v, args...)); } std::ostream& m_os; }; printer out; class scanner { public: scanner(std::istream& is_ = std::cin) : m_is{is_} { m_is.tie(nullptr), std::ios::sync_with_stdio(false); } template T val() { T v; return m_is >> v, v; } template T val(const T offset) { return val() - offset; } template std::vector vec(const int n) { return make_v(n, [this]() { return val(); }); } template std::vector vec(const int n, const T offset) { return make_v(n, [this, offset]() { return val(offset); }); } template std::vector> vvec(const int n0, const int n1) { return make_v(n0, [this, n1]() { return vec(n1); }); } template std::vector> vvec(const int n0, const int n1, const T offset) { return make_v(n0, [this, n1, offset]() { return vec(n1, offset); }); } template auto tup() { return std::tuple...>{val()...}; } template auto tup(const Args&... offsets) { return std::tuple...>{val(offsets)...}; } private: template std::vector make_v(const int n, F f) { std::vector ans; for (int i = 0; i < n; i++) { ans.push_back(f()); } return ans; } std::istream& m_is; }; scanner in; # define SHOW(...) static_cast(0) int main() { auto [A, B] = in.tup(); A = std::abs(A), B = std::abs(B); const ll g = std::gcd(A, B); A /= g, B /= g; const ll R = ((A % 2 == 1 and B % 2 == 1) ? 2 : 1); if (g == 1 and R == 1) { assert(false); // return out.ln(); } ld ans = 0; for (ll i = 0; i <= TEN(6); i += R) { ans += (i + 1) * std::pow((ld)1 / (2 + g * i), 2 + g * i); } out.ln(ans); return 0; }