#include <bits/stdc++.h>
using namespace std;
const long long mod = 100000000;
const long long N = 1007;
double dp[N][N][2];
long long mark[N][N][2];
double func(long long w, long long b, long long turn) {
  if (w == 0) {
    return 0;
  }
  if (b == 0) {
    if (turn == 0) return 1;
    return 0;
  }
  double &ans = dp[w][b][turn];
  if (mark[w][b][turn] != -1) return ans;
  ans = 0;
  if (turn == 0) {
    ans += ((double)w / (double)(b + w)) +
           (((double)b / (double)(b + w)) * (func(w, b - 1, 1)));
  } else {
    if (b >= 2) {
      ans += (((double)b / (double)(b + w)) *
              ((double)(b - 1) / (double)(b + w - 1)) * (func(w, b - 2, 0)));
    }
    ans += (((double)b / (double)(b + w)) *
            ((double)(w) / (double)(b + w - 1)) * (func(w - 1, b - 1, 0)));
  }
  mark[w][b][turn] = 1;
  return ans;
}
int main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  memset(mark, -1, sizeof(mark));
  long long wht, blk;
  cin >> wht >> blk;
  double ans = func(wht, blk, 0);
  cout << fixed << setprecision(9) << ans << endl;
  return 0;
}
