#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for (int i=0; i<(n); ++i)
#define RREP(i, n) for (int i=(int)(n)-1; i>=0; --i)
#define FOR(i, a, n) for (int i=(a); i<(n); ++i)
#define RFOR(i, a, n) for (int i=(int)(n)-1; i>=(a); --i)

#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(),(x).end()

#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl
#define DEBUG(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<<endl;

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[";
  REP(i, SZ(v)) {
    if (i) os << ", ";
    os << v[i];
  }
  return os << "]";
}

template<class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  return os << "(" << p.first << " " << p.second << ")";
}

template<class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template<class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vi>;
using vvll = vector<vll>;

const ll MOD = 1e9 + 7;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
const ld eps = 1e-9;

ld ans = 0.0;
bool sel[2020][2020];
int ofs = 1005;
vll dx, dy;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);

  ll a, b; cin >> a >> b;
  dx = {a, a, -a, -a, b, b, -b, -b};
  dy = {b, -b, b, -b, a, -a, a, -a};

  queue<pair<ll, ll>> que;
  que.push({1, 1});
  while(!que.empty()) {
    ll x, y;
    tie(x, y) = que.front(); que.pop();
    if(sel[x+ofs][y+ofs]) continue;
    sel[x+ofs][y+ofs] = true;
    if(x > 0 && y > 0 && x + y <= 15) {
      ans += 1.0 / pow(x + y, x + y);
    }
    REP(i, 8) {
      ll nx = x + dx[i];
      ll ny = y + dy[i];
      if(abs(nx) + abs(ny) <= 1000 && !sel[nx+ofs][ny+ofs]) que.push({nx, ny});
    }
  }
  cout << ans << endl;

  return 0;
}