#include <bits/stdc++.h>
using namespace std;
const int N = 1e3;
int n, m;
double f[N + 2][N + 2];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i <= n; ++i) {
    for (int j = 0; j <= m; ++j) {
      if (i == 0 && j == 0) continue;
      if (j == 0) {
        f[i][j] = 1;
        continue;
      }
      if (i == 0) {
        f[i][j] = 0;
        continue;
      }
      f[i][j] = 1.0 * i / (i + j);
      if (j >= 3)
        f[i][j] += 1.0 * j / (i + j) * (j - 1) / (i + j - 1) * (j - 2) /
                   (i + j - 2) * f[i][j - 3];
      if (j >= 2)
        f[i][j] += 1.0 * j / (i + j) * (j - 1) / (i + j - 1) * i / (i + j - 2) *
                   f[i - 1][j - 2];
    }
  }
  printf("%.9lf\n", f[n][m]);
  return 0;
}
