#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
double P[1002][1002];
int W, B;
int main() {
  cin >> W >> B;
  for (int i = 1; i <= W; ++i) P[i][0] = 1;
  for (int i = 1; i <= W; ++i)
    for (int j = 1; j <= B; ++j) {
      P[i][j] = (1.0 * i / (i + j));
      if (i >= 1 && j >= 2)
        P[i][j] += (1.0 * j / (i + j)) * (1.0 * (j - 1) / (i + j - 1)) *
                   (1.0 * i / (i + j - 2)) * P[i - 1][j - 2];
      if (j >= 3)
        P[i][j] += (1.0 * j / (i + j)) * (1.0 * (j - 1) / (i + j - 1)) *
                   (1.0 * (j - 2) / (i + j - 2)) * P[i][j - 3];
    }
  cout << fixed << setprecision(9) << P[W][B];
}
