#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdint>
#include <cstdlib>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include <vector>

/* template start */

using i64 = std::int_fast64_t;
using u64 = std::uint_fast64_t;

#define rep(i, a, b) for (i64 i = (a); (i) < (b); (i)++)
#define all(i) i.begin(), i.end()

#ifdef LOCAL
#define debug(...)                                                    \
  std::cerr << "LINE: " << __LINE__ << "  [" << #__VA_ARGS__ << "]:", \
      debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out() { std::cerr << std::endl; }

template <typename Head, typename... Tail>
void debug_out(Head h, Tail... t) {
  std::cerr << " " << h;
  if (sizeof...(t) > 0) std::cout << " :";
  debug_out(t...);
}

template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, std::pair<T1, T2> pa) {
  return os << pa.first << " " << pa.second;
}

template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
  for (std::size_t i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  return os;
}

template <typename T1, typename T2>
inline bool chmax(T1& a, T2 b) {
  return a < b && (a = b, true);
}

template <typename T1, typename T2>
inline bool chmin(T1& a, T2 b) {
  return a > b && (a = b, true);
}

template <typename Num>
constexpr Num mypow(Num a, u64 b, Num id = 1) {
  if (b == 0) return id;
  Num x = id;
  while (b > 0) {
    if (b & 1) x *= a;
    a *= a;
    b >>= 1;
  }
  return x;
}

template <typename T>
std::vector<std::pair<std::size_t, T>> enumerate(const std::vector<T>& data) {
  std::vector<std::pair<std::size_t, T>> ret;
  for (std::size_t index = 0; index < data.size(); index++)
    ret.emplace_back(index, data[index]);
  return ret;
}

/* template end */

i64 extgcd(i64 a, i64 b, i64& x, i64& y) {
  for (i64 u = y = 1, v = x = 0; a;) {
    i64 q = b / a;
    std::swap(x -= q * u, u);
    std::swap(y -= q * v, v);
    std::swap(b -= q * a, a);
  }

  return b;
}

int main() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);

  i64 a, b;
  std::cin >> a >> b;

  a = std::abs(a);
  b = std::abs(b);

  if (a == 0 || b == 0) {
    if (b != 0) std::swap(a, b);

    long double ans = 0.0l;

    rep(n, 1, 101) {
      rep(m, 1, 101) {
        if((n-1)%a!=0||(m-1)%a!=0)continue;
        
        i64 s = (n-1)%a;
        i64 u = (m-1)%a;

        s = (s + 2000000000000000000l) % 2;
        u = (u + 2000000000000000000l) % 2;
        if(s==u)ans += mypow(1.0l / (n + m), n + m);
      }
    }

    std::cout << std::setprecision(19) << ans << "\n";

    return 0;
  }

  i64 g = std::gcd(a, b);

  long double ans = 0.0l;

  rep(n, 1, 101) {
    rep(m, 1, 101) {
      if ((n - 1) % g != 0 || (m - 1) % g != 0) continue;
      i64 s, t, u, v;
      extgcd(a, b, s, t);
      s = (s + 2000000000000000000l) % 2;
      t = (t + 2000000000000000000l) % 2;

      u = s;
      v = t;
      s *= ((n - 1) / g) % 2;
      t *= ((n - 1) / g) % 2;
      u *= ((m - 1) / g) % 2;
      v *= ((m - 1) / g) % 2;

      if ((s + t) % 2 == (u + v) % 2) {
        ans += mypow(1.0l / (n + m), n + m);
      } else if ((a - b + 2000000000000000000l) % 2 == 1) {
        ans += mypow(1.0l / (n + m), n + m);
      }
    }
  }

  std::cout << std::setprecision(19) << ans << "\n";

  return 0;
}