#include <bits/stdc++.h>
using namespace std;
double dp[1010][1010];
int main() {
  int i, j, k, w, b, n, m, y;
  cin >> n >> m;
  for (i = 0; i <= m; i++) dp[0][i] = 0;
  for (i = 0; i <= n; i++) dp[i][0] = 1;
  dp[0][0] = 0;
  for (i = 1; i <= n; i++) {
    for (j = 1; j <= m; j++) {
      int b = j, w = i;
      dp[i][j] = (double)(w) / (w + b);
      if (b >= 3)
        dp[i][j] += (double)b / (w + b) * (double)(b - 1) / (w + b - 1) *
                    (double)(b - 2) / (w + b - 2) * dp[w][b - 3];
      if (b >= 2)
        dp[i][j] += (double)b / (w + b) * (double)(b - 1) / (w + b - 1) *
                    (double)(w) / (w + b - 2) * dp[w - 1][b - 2];
    }
  }
  printf(
      "%"
      "0.9lf"
      " ",
      dp[n][m]);
  return 0;
}
