#include <bits/stdc++.h>
using namespace std;
double dp[1002][1002][2];
double solve(int w, int b, bool pTurn)
{
    if (b <= 0 && pTurn)
        return 1;
    if (w <= 0 || (b <= 0 && !pTurn))
        return 0;
    if (pTurn) {
        double lose = (double)  b / (w + b);
        double win = 1 - lose;
        return dp[w][b][pTurn] = win + lose * solve(w, b - 1, false);
    }
    if(dp[w][b][pTurn] != -1)
        return dp[w][b][pTurn];
    else {
        double lose = (double) b / (w + b);
        double wEsc = (double) w / (w + b - 1);
        double bEsc = (double) (b - 1) / (w + b - 1);
        return dp[w][b][pTurn] =  (double) lose * (wEsc * solve(w - 1, b - 1, true) + bEsc * solve(w, b - 2, true));
    }
}

int main()
{
    double w, b;
    cin >> w >> b;
    memset(dp, -1, sizeof(dp));
    printf("%0.9f", solve(w, b, true));
}