/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.10.30 22:15:35
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;

int main() {
    ll a,b;cin >> a >> b;
    if (a == 0 && b == 0) {
        cout << 0.25 << endl;
        return 0;
    }
    else if (a == 0 || b == 0) {
        a = a+b;
        a = abs(a);
        double ans = 0;
        for (int i = 0; i <= 1000000/a; i++) {
            ans += 1.0/pow(i*a+2,i*a+2);
        }
        printf("%.10f\n",ans);
        return 0;
    }
    a = abs(a);
    b = abs(b);
    ll g = __gcd(a,b);
    double ans = 0;
    for (int i = 0; i <= 1000000/g; i++) {
        ans += 1.0/pow(i*g+2,i*g+2)*(i+1);
    }
    printf("%.10f\n",ans);
    return 0;
}