#include <bits/stdc++.h>
using namespace std;
long double a[2000][2000];
int main() {
  int w, b, i1, j1;
  long double i, j;
  cout.precision(12);
  cin >> w >> b;
  for (i1 = 0; i1 <= w; i1++)
    for (j1 = 0; j1 <= b; j1++) a[i1][j1] = 0;
  for (i1 = 1; i1 <= w; i1++) a[i1][0] = 1;
  for (i1 = 1; i1 <= w; i1++)
    for (j1 = 1; j1 <= b; j1++) {
      i = (long double)i1;
      j = (long double)j1;
      a[i1][j1] += i / (i + j);
      if (j >= 3)
        a[i1][j1] += j / (i + j) * (j - 1) / (i + j - 1) * (j - 2) /
                     (i + j - 2) * a[i1][j1 - 3];
      if (j >= 2)
        a[i1][j1] += j / (i + j) * (j - 1) / (i + j - 1) * i / (i + j - 2) *
                     a[i1 - 1][j1 - 2];
    }
  cout << a[w][b];
  return 0;
}
