#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
const int N = 1000002;
const double PI = 4 * atan(1);
const double eps = 1e-7;
const long long oo = 1e18;
long double dp[1005][1005][2];
long long w, b;
long double solve(long long w, long long b, long long wo) {
  if (w == 0) {
    if (wo == 0)
      return 0.0;
    else
      return 1.0;
  }
  if (dp[w][b][wo] >= 0) return dp[w][b][wo];
  long double to = 0.0;
  if (wo == 0) {
    if (b == 0) {
      to = 1;
    } else {
      to = (long double)(w / (1.0 * (w + b))) +
           ((b / (1.0 * (w + b)))) * (1 - solve(w, b - 1, 1 - wo));
    }
  } else {
    if (b == 0) {
      to = 1;
    } else {
      to = (long double)(w / (1.0 * (w + b))) +
           ((b / (1.0 * (w + b)))) *
               (1 -
                (long double)(w / (1.0 * (w + b - 1))) *
                    solve(w - 1, b - 1, 1 - wo) -
                (long double)((b - 1) / (1.0 * (w + b - 1))) *
                    solve(w, b - 2, 1 - wo));
    }
  }
  return dp[w][b][wo] = to;
}
int main() {
  ios::sync_with_stdio(0);
  for (int i = 0; i <= 1000; i++) {
    for (int j = 0; j <= 1000; j++) {
      for (int k = 0; k < 2; k++) {
        dp[i][j][k] = -1;
      }
    }
  }
  cin >> w >> b;
  long double ans = solve(w, b, 0);
  printf("%.10Lf", ans);
  return 0;
}
