#include <bits/stdc++.h>
using namespace std;
double dp[1005][1005];
int main() {
  int i, j, w, b;
  double ans = 0.0;
  while (cin >> w >> b) {
    memset(dp, 0, sizeof(dp));
    for (i = 0; i <= b; i++) dp[0][i] = 0;
    for (i = 1; i <= w; i++) dp[i][0] = 1.0;
    for (i = 1; i <= w; i++) {
      for (j = 1; j <= b; j++) {
        dp[i][j] += (double)i / (i + j);
        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];
        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];
      }
    }
    printf("%.9f\n", dp[w][b]);
  }
  return 0;
}
