#include // created [2019/12/18] 00:09:13 #pragma GCC diagnostic ignored "-Wsign-compare" #pragma GCC diagnostic ignored "-Wsign-conversion" using i32 = int32_t; using i64 = int64_t; using u32 = uint32_t; using u64 = uint64_t; using uint = unsigned int; using usize = std::size_t; using ll = long long; using ull = unsigned long long; using ld = long double; template using arr = T (&)[n]; template using c_arr = const T (&)[n]; template constexpr T popcount(const T u) { return u ? static_cast(__builtin_popcountll(static_cast(u))) : static_cast(0); } template constexpr T log2p1(const T u) { return u ? static_cast(64 - __builtin_clzll(static_cast(u))) : static_cast(0); } template constexpr T msbp1(const T u) { return log2p1(u); } template constexpr T lsbp1(const T u) { return __builtin_ffsll(u); } template constexpr T clog(const T u) { return u ? log2p1(u - 1) : static_cast(u); } template constexpr bool ispow2(const T u) { return u and (static_cast(u) & static_cast(u - 1)) == 0; } template constexpr T ceil2(const T u) { return static_cast(1) << clog(u); } template constexpr T floor2(const T u) { return u == 0 ? static_cast(0) : static_cast(1) << (log2p1(u) - 1); } template constexpr bool btest(const T mask, const usize ind) { return static_cast((static_cast(mask) >> ind) & static_cast(1)); } template void bset(T& mask, const usize ind) { mask |= (static_cast(1) << ind); } template void breset(T& mask, const usize ind) { mask &= ~(static_cast(1) << ind); } template void bflip(T& mask, const usize ind) { mask ^= (static_cast(1) << ind); } template void bset(T& mask, const usize ind, const bool b) { (b ? bset(mask, ind) : breset(mask, ind)); } template constexpr T bcut(const T mask, const usize ind) { return ind == 0 ? static_cast(0) : static_cast((static_cast(mask) << (64 - ind)) >> (64 - 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); } constexpr unsigned int mod = 1000000007; template constexpr T inf_v = std::numeric_limits::max() / 4; template constexpr Real pi_v = Real{3.141592653589793238462643383279502884}; auto mfp = [](auto&& f) { return [=](auto&&... args) { return f(f, std::forward(args)...); }; }; template T in() { T v; return std::cin >> v, v; } template T in_v(typename std::enable_if<(i == n), c_arr>::type) { return in(); } template auto in_v(typename std::enable_if<(i < n), c_arr>::type& szs) { const usize s = (usize)szs[i]; std::vector(szs))> ans(s); for (usize j = 0; j < s; j++) { ans[j] = in_v(szs); } return ans; } template auto in_v(c_arr szs) { return in_v(szs); } template auto in_t() { return std::tuple...>{in()...}; } struct io_init { io_init() { std::cin.tie(nullptr), std::ios::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(20); } } hogechan; template int out(const T& v) { return std::cout << v, 0; } template int out(const std::vector& v) { for (usize i = 0; i < v.size(); i++) { if (i > 0) { std::cout << ' '; } out(v[i]); } return std::cout << "\n", 0; } template int out(const std::pair& v) { return out(v.first), std::cout << ' ', out(v.second), 0; } template int out(const T& v, const Args... args) { return out(v), std::cout << ' ', out(args...), 0; } template int outln(const Args... args) { return out(args...), std::cout << '\n', 0; } template void outel(const Args... args) { return out(args...), std::cout << std::endl, 0; } # define SHOW(...) static_cast(0) constexpr ull TEN(const usize n) { return n == 0 ? 1ULL : TEN(n - 1) * 10ULL; } template auto make_v(typename std::enable_if<(i == n), c_arr>::type, const T& v = T{}) { return v; } template auto make_v(typename std::enable_if<(i < n), c_arr>::type szs, const T& v = T{}) { const usize s = (usize)szs[i]; return std::vector(szs, v))>(s, make_v(szs, v)); } template auto make_v(c_arr szs, const T& t = T{}) { return make_v(szs, t); } using namespace std; template class AMP : public deque { private: static constexpr int root = 5; static constexpr int MOD_ = 924844033; static void trim_digit(AMP& num) { while ((int)num.size() >= 1 && num.back() == 0) num.pop_back(); if ((int)num.size() == 1 && num[0] == 0) { num.zero = true; return; } while ((int)num.size() < acc) num.push_front(0), num.ex--; while ((int)num.size() > acc + 1) num.pop_front(), num.ex++; rounding(num); } static void rounding(AMP& num) { if ((int)num.size() != acc + 1) return; if (num[0] >= 5) { int pos = 1; do { num[pos]++; if (num[pos] != 10) break; num[pos] = 0; } while (++pos <= acc); if (pos == acc + 1) num.push_back(1), num.pop_back(), num.ex++; } num.pop_front(), num.ex++; } static bool abs_less(const AMP& a, const AMP& b) { if (a.ex != b.ex) return a.ex < b.ex; for (int index = acc - 1; index >= 0; index--) { if (a[index] != b[index]) return a[index] < b[index]; } return false; } static void num_sbst(AMP& a, const AMP& b) { a.resize(acc), a.zero = false, a.ex = b.ex; for (int i = 0; i < acc; i++) a[i] = b[i]; } static void add(const AMP& a, const AMP& b, AMP& res) { int diff = a.ex - b.ex, carry = 0; if (abs(diff) > acc) return (diff > 0) ? num_sbst(res, a) : num_sbst(res, b); if (diff >= 0) { num_sbst(res, a); if (diff) res.push_front(0), res.ex--; for (int i = !diff; i <= acc; i++) { int val = res[i - !diff] + (i <= acc - diff ? b[i + diff - 1] : 0) + carry; carry = val / 10; res[i - !diff] = val % 10; } if (carry) res.push_back(1); } else { num_sbst(res, b); res.push_front(0), res.ex--; for (int i = 0; i <= acc; i++) { int val = res[i] + (i <= acc + diff ? a[i - diff - 1] : 0) + carry; carry = val / 10; res[i] = val % 10; } if (carry) res.push_back(1); } trim_digit(res); } static void sub(const AMP& a, const AMP& b, AMP& res) { int diff = a.ex - b.ex, carry = 0; num_sbst(res, a); if (diff > acc) return; if (diff) { res.push_front(0), res.ex--; int carry = 0; for (int i = 0; i <= acc; i++) { int val = res[i] - carry - (i <= acc - diff ? b[i + diff - 1] : 0); if (val < 0) { carry = 1, val += 10; } else { carry = 0; } res[i] = val; } } else { for (int i = 0; i < acc; i++) { int val = res[i] - carry - b[i]; if (val < 0) { carry = 1, val += 10; } else { carry = 0; } res[i] = val; } } trim_digit(res); } static int add_(const int x, const int y) { return (x + y < MOD_) ? x + y : x + y - MOD_; } static int mul_(const int x, const int y) { return (long long)x * y % MOD_; } static int power(int x, int n) { int res = 1; while (n > 0) { if (n & 1) res = mul_(res, x); x = mul_(x, x); n >>= 1; } return res; } static int inverse(const int x) { return power(x, MOD_ - 2); } static void ntt(vector& a, const bool rev = false) { int i, j, k, s, t, v, w, wn; const int size = (int)a.size(); const int height = (int)log2(2 * size - 1); for (i = 0; i < size; i++) { j = 0; for (k = 0; k < height; k++) j |= (i >> k & 1) << (height - 1 - k); if (i < j) std::swap(a[i], a[j]); } for (i = 1; i < size; i *= 2) { w = power(root, (MOD_ - 1) / (i * 2)); if (rev) w = inverse(w); for (j = 0; j < size; j += i * 2) { wn = 1; for (k = 0; k < i; k++) { s = a[j + k], t = mul_(a[j + k + i], wn); a[j + k] = add_(s, t); a[j + k + i] = add_(s, MOD_ - t); wn = mul_(wn, w); } } } if (rev) { v = inverse(size); for (i = 0; i < size; i++) a[i] = mul_(a[i], v); } } static void mul(const AMP& a, const AMP& b, AMP& res) { const int size = (int)a.size() + (int)b.size() - 1; int t = 1; while (t < size) t <<= 1; vector A(t, 0), B(t, 0); for (int i = 0; i < (int)a.size(); i++) A[i] = a[i]; for (int i = 0; i < (int)b.size(); i++) B[i] = b[i]; ntt(A), ntt(B); for (int i = 0; i < t; i++) A[i] = mul_(A[i], B[i]); ntt(A, true); res.resize(size); int carry = 0; for (int i = 0; i < size; i++) { int val = A[i] + carry; carry = val / 10; res[i] = val % 10; } if (carry) res.push_back(carry); trim_digit(res); } class MPI : public deque { public: MPI() { push_back(0); } inline static void trim_digit(MPI& num) { while (num.back() == 0 && (int)num.size() >= 2) num.pop_back(); } bool isZero() const { return (int)size() == 1 && (*this)[0] == 0; } static void add(const MPI& a, const MPI& b, MPI& res) { res = a; int mx = (int)max(a.size(), b.size()); res.resize(mx, 0); int carry = 0; for (int i = 0; i < mx; i++) { int val = res[i] + ((i < (int)b.size()) ? b[i] : 0) + carry; carry = val / 10; res[i] = val % 10; } if (carry) res.push_back(1); } static void sub(const MPI& a, const MPI& b, MPI& res) { res = a; int carry = 0; for (int i = 0; i < (int)res.size(); i++) { int val = res[i] - carry - ((i < (int)b.size()) ? b[i] : 0); if (val < 0) { carry = 1, val += 10; } else { carry = 0; } res[i] = val; } trim_digit(res); } bool operator<(const MPI& another) const { if (size() != another.size()) return size() < another.size(); for (int index = (int)size() - 1; index >= 0; index--) { if ((*this)[index] != another[index]) return (*this)[index] < another[index]; } return false; } static bool div_geq(const MPI& mod, const MPI& num) { if ((int)mod.size() != (int)num.size()) return (int)mod.size() > (int)num.size(); int n = (int)mod.size(); for (int i = 0; i < n; i++) { if (mod[n - 1 - i] != num[n - 1 - i]) { return mod[n - 1 - i] > num[n - 1 - i]; } } return true; } static void div_(const MPI& a, const MPI& b, MPI& res) { vector mult(9); MPI mod; mult[0] = b; for (int i = 0; i < 8; i++) add(mult[i], b, mult[i + 1]); for (int i = (int)a.size() - 1; i >= 0; i--) { if (mod.isZero()) { mod.back() = a[i]; } else { mod.push_front(a[i]); } if (div_geq(mod, b)) { int l = 0, r = 9; while (r - l > 1) { int mid = (l + r) / 2; if (mod < mult[mid]) { r = mid; } else { l = mid; } } MPI mod_ = mod; sub(mod_, mult[l], mod); res.push_front(l + 1); } else { res.push_front(0); } } trim_digit(res); } }; static void mpi_AMP(MPI& a, const AMP& b) { if (b.zero) { a = MPI(); return; } int n = (int)b.size(); a.resize(n); for (int i = 0; i < n; i++) a[i] = b[i]; } static void AMP_mpi(AMP& a, const MPI& b) { if (b.isZero()) { a = AMP(); return; } int n = (int)b.size(); a.resize(n); for (int i = 0; i < n; i++) a[i] = b[i]; } public: friend ostream& operator<<(ostream& os, const AMP& num) { if (num.zero) { os << "0."; for (int i = 0; i < acc - 1; i++) os << '0'; os << "+e0"; return os; } if (num.sign) os << '-'; os << num.back() << '.'; for (int i = 0; i < acc - 1; i++) os << num[acc - 2 - i]; os << 'e'; if (num.ex + acc - 1 >= 0) os << '+'; os << num.ex + acc - 1; return os; } friend istream& operator>>(istream& is, AMP& num) { string s; is >> s; num = AMP(s); return is; } void print_decimal(int decimal) const { if (zero) { cout << "0."; for (int i = 0; i < decimal; i++) cout << '0'; } if (sign) cout << '-'; for (int i = max(ex + acc - 1, 0LL); i >= -decimal; i--) { cout << ((i - ex >= 0 || i - ex >= acc) ? (*this)[i - ex] : '0'); if (i == 0) cout << '.'; } } double to_double() const { if (zero) { return 0.0; } double res = 0.0, d = 1.0; for (int i = 0; i < acc; i++) { res += (*this)[i] * d, d *= 10.0; } return res * pow(10.0, ex); } AMP& operator=(long long num) { *this = AMP(num); return *this; } bool operator<(const AMP& num) const { if (zero) return !num.zero && !num.sign; if (num.zero) return sign; if (sign ^ num.sign) return sign; if (ex != num.ex) return (ex < num.ex) ^ sign; for (int index = acc - 1; index >= 0; index--) { if ((*this)[index] != num[index]) return ((*this)[index] < num[index]) ^ sign; } return false; } bool operator<(const long long num) const { return *this < AMP(num); } friend bool operator<(const long long num, const AMP& another) { return AMP(num) < another; } bool operator>(const AMP& num) const { return num < *this; } bool operator>(const long long num) const { return *this > AMP(num); } friend bool operator>(const long long num, const AMP& another) { return AMP(num) > another; } bool operator<=(const AMP& num) const { return !(*this > num); } bool operator<=(const long long num) const { return *this <= AMP(num); } friend bool operator<=(const long long num, const AMP& another) { return AMP(num) <= another; } bool operator>=(const AMP& num) const { return !(*this < num); } bool operator>=(const long long num) const { return *this >= AMP(num); } friend bool operator>=(const long long num, const AMP& another) { return AMP(num) >= another; } bool operator==(const AMP& num) const { if (zero || num.zero) return zero && num.zero; if (sign ^ num.sign) return false; if (ex != num.ex) return false; for (int index = acc - 1; index >= 0; index--) { if ((*this)[index] != num[index]) return false; } return true; } bool operator==(const long long num) const { return *this == AMP(num); } friend bool operator==(const long long num, const AMP& another) { return AMP(num) == another; } bool operator!=(const AMP& num) const { return !(*this == num); } bool operator!=(const long long num) const { return *this != AMP(num); } friend bool operator!=(const long long num, const AMP& another) { return AMP(num) != another; } explicit operator bool() const noexcept { return !zero; } bool operator!() const noexcept { return !static_cast(*this); } explicit operator int() const noexcept { return (int)this->to_ll(); } explicit operator long long() const noexcept { return this->to_ll(); } AMP operator+() const { return *this; } AMP operator-() const { AMP res = *this; res.sign = !sign; return res; } friend AMP abs(const AMP& num) { AMP res = num; res.sign = false; return res; } AMP operator+(const AMP& num) const { if (zero) { AMP res = num; return res; } if (num.zero) { AMP res = *this; return res; } AMP res; res.sign = sign; if (sign != num.sign) { if (abs_less(*this, num)) { res.sign = num.sign; sub(num, *this, res); return res; } else { sub(*this, num, res); return res; } } add(*this, num, res); return res; } AMP operator+(long long num) const { return *this + AMP(num); } friend AMP operator+(long long a, const AMP& b) { return b + a; } AMP& operator+=(const AMP& num) { *this = *this + num; return *this; } AMP& operator+=(long long num) { *this = *this + num; return *this; } AMP& operator++() { return *this += 1; } AMP operator++(int) { AMP res = *this; *this += 1; return res; } AMP operator-(const AMP& num) const { if (zero) { AMP res = num; res.sign = !res.sign; return res; } if (num.zero) { AMP res = *this; return res; } AMP res; res.sign = sign; if (sign != num.sign) { add(*this, num, res); return res; } if (abs_less(*this, num)) { res.sign = !sign; sub(num, *this, res); } else { sub(*this, num, res); } return res; } AMP operator-(long long num) const { return *this - AMP(num); } friend AMP operator-(long long a, const AMP& b) { return AMP(a) - b; } AMP& operator-=(const AMP& num) { *this = *this - num; return *this; } AMP& operator-=(long long num) { *this = *this - num; return *this; } AMP& operator--() { return *this -= 1; } AMP operator--(int) { AMP res = *this; *this -= 1; return res; } AMP operator*(const AMP& num) const { if (zero || num.zero) return AMP(); AMP res; res.zero = false; res.sign = (sign ^ num.sign); res.ex = ex + num.ex; mul(*this, num, res); return res; } AMP operator*(long long num) const { return *this * AMP(num); } friend AMP operator*(long long a, const AMP& b) { return b * a; } AMP& operator*=(const AMP& num) { *this = *this * num; return *this; } AMP& operator*=(long long num) { *this = *this * num; return *this; } AMP operator/(const AMP& num) const { assert(!num.zero); if (zero) { return AMP(); } MPI kp, res_, num_; mpi_AMP(num_, num); AMP res; res.zero = false; res.sign = (sign ^ num.sign); res.ex = ex - num.ex; mpi_AMP(kp, *this); if (abs_less(*this, num)) kp.push_front(0), res.ex--; for (int i = 0; i < acc; i++) kp.push_front(0), res.ex--; MPI::div_(kp, num_, res_); AMP_mpi(res, res_); trim_digit(res); return res; } AMP operator/(long long num) const { return *this / AMP(num); } friend AMP operator/(long long a, const AMP& b) { return AMP(a) / b; } AMP& operator/=(const AMP& num) { *this = *this / num; return *this; } AMP& operator/=(long long num) { *this = *this / num; return *this; } AMP div2() const { if (zero) return AMP(); AMP res = *this; int carry = 0; for (int i = acc - 1; i >= 0; i--) { int val = (*this)[i] + carry * 10; carry = val % 2; if (i != acc - 1 || val >= 2) { res[i] = val / 2; } else { res[i] = 0; } } if (carry) res.push_front(5), res.ex--; trim_digit(res); return res; } friend AMP sqrt(AMP x) { if (x <= AMP(0)) return AMP(); AMP s = 1, t = x; while (s < t) { s = s + s, t = t.div2(); } do { t = s, s = (x / s + s).div2(); } while (s < t); trim_digit(t); return t; } friend AMP log10(const AMP& x) { assert(x > AMP(0)); return AMP(acc + x.ex); } friend AMP pow(AMP a, long long b) { if (a.zero) return AMP(); assert(b >= 0); AMP res(1); while (b) { if (b % 2) res *= a; a *= a; b = b / 2; } return res; } bool sign, zero; long long ex; AMP() : zero(true) {} AMP(long long val) : sign(false), zero(false), ex(0) { if (val == 0) { zero = true; return; } if (val < 0) sign = true, val = -val; while (val) push_back(val % 10), val /= 10; trim_digit(*this); } AMP(const string& s) : sign(false), zero(false), ex(0) { if (s.empty() || s == "0") { zero = true; return; } if (s[0] == '-') sign = true; for (int i = (int)s.size() - 1; i >= sign; i--) { if (s[i] == '.') { ex = i + 1 - (int)s.size(); } else { push_back(s[i] - '0'); } } trim_digit(*this); } }; int main() { using ld = AMP<256>; const auto [A, B, C] = in_t(); const auto [a, b, c] = std::tuple(A, B, C); if (A == 0) { if (B == 0) { if (C == 0) { return outln(-1); } else { return outln(0); } } else { outln(1); outln((-c / b).to_double()); return 0; } } else { const ll D = B * B - 4LL * A * C; const ld d = D; if (D < 0) { return outln(0); } else if (D == 0) { outln(1); outln((-b / (2 * a)).to_double()); return 0; } else { const ld s = sqrt(d); outln(2); ld x1 = (-b + s) / (2 * a); ld x2 = (-b - s) / (2 * a); if (x1 > x2) { std::swap(x1, x2); } outln(x1.to_double()); outln(x2.to_double()); return 0; } } return 0; }