#include <bits/stdc++.h>
using namespace std;
double dp[1005][1005];
int main() {
  int w, b;
  cin >> w >> b;
  memset(dp, 0, sizeof(dp));
  for (int i = 1; i <= w; i++) dp[i][0] = 1;
  for (int i = 1; i <= b; i++) dp[0][i] = 0;
  for (int i = 1; i <= w; i++) {
    for (int j = 1; j <= b; j++) {
      dp[i][j] += (double)i / (i + j);
      if (j >= 2)
        dp[i][j] += (double)j / (i + j) * (double)(j - 1) / (i + j - 1) *
                    (double)i / (i + j - 2) * dp[i - 1][j - 2];
      if (j >= 3)
        dp[i][j] += (double)j / (i + j) * (double)(j - 1) / (i + j - 1) *
                    (double)(j - 2) / (i + j - 2) * dp[i][j - 3];
    }
  }
  printf("%.9f\n", dp[w][b]);
  return 0;
}
