撰写#include<cstdio>
#include<string>
#include<cstring>
#include<iostream>
#include<algorithm>
#define M 5005
using namespace std;
int r,b;
double f[2][M];
int main(){
scanf("%d%d",&r,&b);
int tmp=0;
for(int i=1;i<=r;i++){
tmp=tmp^1;
f[tmp][0]=i;
for(int j=1;j<=b;j++)
f[tmp][j]=max((double)0,(double)i/(i+j)*(f[tmp^1][j]+1)+(double)j/(i+j)*(f[tmp][j-1]-1));
}
long long ans=f[r&1][b]*1000000;
printf("%f",(double)ans/1000000);
return 0;
}