#include <bits/stdc++.h>
using namespace std;
double dp[1005][1005];
int main() {
  int w, b;
  scanf("%d%d", &w, &b);
  for (int i = 0; i <= b; i++) dp[0][i] = 0.0;
  for (int j = 1; j <= w; j++) dp[j][0] = 1.0;
  for (int i = 1; i <= w; i++) {
    for (int j = 1; j <= b; j++) {
      dp[i][j] = (double)(i) / (j + i);
      if (j >= 3)
        dp[i][j] += 1.0 * j / (i + j) * 1.0 * (j - 1) / (i + j - 1) * (j - 2) /
                    (i + j - 2) * dp[i][j - 3];
      if (j >= 2)
        dp[i][j] += 1.0 * j / (i + j) * 1.0 * (j - 1) / (i + j - 1) * (i) /
                    (i + j - 2) * dp[i - 1][j - 2];
    }
  }
  printf("%.9f", dp[w][b]);
}
