#include <bits/stdc++.h>
using namespace std;
vector<long long> ve[100005];
long double dp[1005][1005];
long double recur(long long w, long long b) {
  if (w == 0) return 0.0;
  if (b <= 0) return 1.0;
  long double win = ((long double)w / (w + b));
  if (b == 1) return win;
  if (dp[w][b] != 0.0) return dp[w][b];
  long double fpart = (long double)((b - 1) * b) / ((w + b) * (w + b - 1));
  long double part1 = ((long double)(w) / (w + b - 2)) * recur(w - 1, b - 2);
  long double part2 = ((long double)(b - 2) / (w + b - 2)) * recur(w, b - 3);
  return dp[w][b] = (win + (fpart) * (part1 + part2));
}
void solve() {
  vector<long long> v;
  vector<pair<long long, long long>> vp;
  map<long long, long long> mp;
  set<long long> st;
  multiset<long long> mst;
  long long w, b;
  cin >> w >> b;
  long double ans = recur(w, b);
  cout << setprecision(15) << ans << '\n';
}
bool imp = false;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t = 1;
  if (imp) cin >> t;
  long long j = t;
  while (t--) {
    solve();
  }
  return 0;
}
