#include<iostream>
#include<iomanip>
#include<cstdio>
using namespace std;
long A,B;
long gcd(long a,long b){return b?gcd(b,a%b):a;}
main()
{
	cin>>A>>B;
	long g=gcd(A,B);
	if(g<0)g=-g;
	double ans=0;
	for(int i=2;;i++)
	{
		long u=2+g*(i-2);
		if(u>20)break;
		double now=i-1;
		for(int j=0;j<u;j++)now/=u;
		ans+=now;
	}
	cout<<fixed<<setprecision(16)<<ans<<endl;
}