#include <bits/stdc++.h>
double p[1005][1005], d[1005][1005];
int w, b;
int main() {
  int i, j;
  scanf("%d%d", &w, &b);
  for (i = 1; i <= w; i++) p[i][0] = 1.0;
  for (i = 1; i <= w; i++)
    for (j = 1; j <= b; j++) {
      p[i][j] = 1.0 * i / (i + j) + d[i][j - 1] * j * 1.0 / (i + j);
      d[i][j] = 1.0 * j / (i + j) *
                (p[i - 1][j - 1] * (i)*1.0 / (i + j - 1) +
                 p[i][j - 2] * 1.0 * (j - 1) / (i + j - 1));
    }
  printf("%.9lf\n", p[w][b]);
  return 0;
}
