#include <bits/stdc++.h>
using namespace std;
int w, b;
double ans, f[1005][1005];
int main() {
  scanf("%d%d", &w, &b);
  for (int i = 1; i <= w; i++) f[i][0] = 1;
  for (int ii = 1; ii <= w; ii++)
    for (int jj = 1; jj <= b; jj++) {
      double i = ii, j = jj;
      f[ii][jj] += i / (i + j);
      if (jj >= 3)
        f[ii][jj] += j / (i + j) * (j - 1) / (i + j - 1) * (j - 2) /
                     (i + j - 2) * f[ii][jj - 3];
      if (jj >= 2)
        f[ii][jj] += j / (i + j) * (j - 1) / (i + j - 1) * i / (i + j - 2) *
                     f[ii - 1][jj - 2];
    }
  printf("%.9lf", f[w][b]);
}
