#include <bits/stdc++.h>
using namespace std;
int w, b, sum;
double ans, q;
double p[1010][1010];
int main() {
  scanf("%d%d", &w, &b);
  for (int i = 1; i <= w; ++i) {
    p[i][0] = 1.0;
    p[i][1] = 1.0 * i / (i + 1);
  }
  for (int i = 1; i <= w; ++i)
    for (int j = 2; j <= b; ++j) {
      p[i][j] = 1.0 * i / (i + j);
      p[i][j] += 1.0 * j / (i + j) * (j - 1) / (i + j - 1) * i / (i + j - 2) *
                 p[i - 1][j - 2];
      if (j ^ 2)
        p[i][j] += 1.0 * j / (i + j) * (j - 1) / (i + j - 1) * (j - 2) /
                   (i + j - 2) * p[i][j - 3];
    }
  printf("%0.12lf", p[w][b]);
  return 0;
}
