#include <bits/stdc++.h>
using namespace std;
inline bool isvowel(char ch) {
  ch = tolower(ch);
  return (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u');
}
inline bool isprime(int n) {
  if (n < 2 || (n % 2 == 0 && n != 2)) return false;
  for (int i = 3; i * i <= n; i++)
    if (n % i == 0) return false;
  return true;
}
class Union {
 private:
  vector<int> saizu, link;

 public:
  Union(int n) {
    saizu.assign(n, 1);
    link.resize(n);
    iota(link.begin(), link.end(), 0);
  }
  int find(int n) {
    if (link[n] == n) return n;
    return link[n] = find(link[n]);
  }
  int same(int a, int b) { return find(a) == find(b); }
  void unite(int a, int b) {
    if (same(a, b)) return;
    a = find(a);
    b = find(b);
    if (saizu[a] < saizu[b]) swap(a, b);
    saizu[a] += saizu[b];
    link[b] = a;
  }
  int getsize(int a) { return saizu[find(a)]; }
};
map<pair<int, int>, double> dp;
double calc(int w, int b) {
  if (w <= 0) return 0;
  if (b <= 0) return 1;
  pair<int, int> arg = make_pair(w, b);
  if (dp.find(arg) != dp.end()) return dp[arg];
  double res = w * 1.0 / (w + b), cont = b * 1.0 / (b + w);
  b--;
  cont *= b * 1.0 / (b + w);
  b--;
  if (cont > 1e-13) {
    double p_black = calc(w, b - 1) * (b * 1.0 / (w + b));
    double p_white = calc(w - 1, b) * (w * 1.0 / (w + b));
    res += cont * (p_black + p_white);
  }
  return dp[arg] = res;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int b, w;
  cin >> w >> b;
  cout << fixed << setprecision(10) << calc(w, b);
  return 0;
}
