#include <bits/stdc++.h>
using namespace std;
double arr[2002][1002];
int main() {
  int a, b, c, d, e, f, g, h;
  scanf("%d%d", &a, &b);
  e = a + b;
  arr[e][a] = 1.0;
  f = e;
  double res = 0.0;
  g = 1;
  while (f) {
    if (g) {
      for (d = 1; d <= f; d++) {
        res += arr[f][d] * (double)(d) / (double)(f);
        arr[f - 1][d] += arr[f][d] * (double)(f - d) / (double)(f);
      }
      f -= 1;
    } else {
      if (f < 2) break;
      for (d = 1; d <= f; d++) {
        arr[f - 2][d] += arr[f][d] * (double)(f - d) / (double)(f) *
                         (double)(f - d - 1.0) / (double)(f - 1.0);
        arr[f - 2][d - 1] += arr[f][d] * (double)(f - d) / (double)(f) *
                             (double)(d) / (double)(f - 1.0);
      }
      f -= 2;
    }
    g ^= 1;
  }
  printf("%.9f\n", res);
  return 0;
}
