#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define rep(i,n) for(int i=0; i<(n); i++)

LL GCD(LL a,LL b){ return b?GCD(b,a%b):a; }

double F(double x){ return pow(x,-x); }

int main(){
	LL A,B; cin>>A>>B;
	A=abs(A); B=abs(B);

	double ans=0.;
	if(A!=0 && B!=0){
		LL G=GCD(A,B); A/=G; B/=G;
		if(A%2==1 && B%2==1){rep(x,20)rep(y,20)if((x+y)%2==0)ans+=F(x*G+y*G+2);}
		else rep(x,20)rep(y,20)ans+=F(x*G+y*G+2);
	}
	else if(A==0 && B==0) ans=0.25;
	else rep(x,20)rep(y,20)ans+=F((x+y)*(A+B)+2);

	cout<<fixed<<setprecision(10)<<ans<<endl;
	return 0;
}