#include <bits/stdc++.h>
using namespace std;
int w, b;
double dp[1010][1010][2];
double solve(int a, int b, int k) {
  if (a == 0) return 0.0;
  if (b == 0) {
    if (k == 0)
      return 1.0;
    else
      return 0.0;
  }
  if (dp[a][b][k] >= -0.5) return dp[a][b][k];
  double res = 0;
  if (k == 0) {
    res = (double)a / (a + b) * 1.0 + (double)b / (a + b) * solve(a, b - 1, 1);
  } else {
    res = (double)a / (a + b) * 0.0 + (double)b / (a + b) * (double)a /
                                          (a + b - 1) * solve(a - 1, b - 1, 0);
    if (b != 1)
      res += (double)b / (a + b) * (double)(b - 1) / (a + b - 1) *
             solve(a, b - 2, 0);
  }
  dp[a][b][k] = res;
  return res;
}
int main() {
  cin >> w >> b;
  for (int i = 0; i <= w; i++)
    for (int j = 0; j <= b; j++)
      for (int k = 0; k < 2; k++) dp[i][j][k] = -1;
  double ans = solve(w, b, 0);
  printf("%.12lf\n", ans);
  return 0;
}
