#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7, Base = 998244353;
const long long N = 6e5 + 7;
const long long INF = 1LL * 1000 * 1000 * 1000 * 1000 * 1000 * 1000 + 7LL;
const double pie = acos(-1.0);
double Memo[1001][1001];
double dfs(long long w, long long b, long long princess = 1) {
  double &res = Memo[w][b], W, B;
  if (res != -1.0) return res;
  if (b == 0) {
    if (princess) {
      if (w)
        Memo[w][b] = 1.0;
      else
        Memo[w][b] = 0.0;
    } else
      Memo[w][b] = 0.0;
    return Memo[w][b];
  }
  if (w == 0) return 0;
  res = 0;
  if (princess) {
    res = (double)w / (double)(w + b);
    res += ((double)b / (double)(w + b)) * dfs(w, b - 1, princess ^ 1);
  } else {
    if (b >= 2)
      res += ((double)b / (double)(b + w)) *
             ((double)(b - 1) / (double)(w + b - 1)) *
             dfs(w, b - 2, princess ^ 1);
    res += ((double)b / (double)(w + b)) * ((double)w / (double)(w + b - 1)) *
           dfs(w - 1, b - 1, princess ^ 1);
  }
  return res;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  for (long long i = 0; i <= 1000; ++i) {
    for (long long j = 0; j <= 1000; ++j) {
      Memo[i][j] = -1.0;
    }
  }
  long long w, b;
  cin >> w >> b;
  cout << setprecision(10) << fixed << dfs(w, b) << '\n';
  return 0;
}
