#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={0,0,1,-1,1,1,-1,-1,0};
const ll dx[9]={1,-1,0,0,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}



int main(){
    CST(11);
    ll a,b;cin >> a >> b;
    a=abs(a);b=abs(b);
    if(a==0&&b==0){
        cout << 0.25000000 <<endl;return 0;
    }
    if(a==0||b==0){
        ll z=a;chmax(z,b);// z＋
        long double ans=0;
        ll cnt=1;
        for(int i=2;i<=11;i+=z){
            long double x=1;
            rep(j,i)x/=i;
            ans+=x*cnt;
            cnt++;
        }
        cout << ans <<endl;
        return 0;
    }
    ll g=__gcd(a,b);
    a/=g;b/=g;
    if(g==1){
        if(a%2==0||b%2==0){
            long double ans=0;
            for(int i=2;i<=11;i++){
                long double x=1;
                rep(j,i)x/=i;
                ans+=x*(i-1);
            }
            cout << ans <<endl;
        }
        else{
            long double ans=0;
            for(int i=2;i<=11;i++){
                if(i%2)continue;
                long double x=1;
                rep(j,i)x/=i;
                ans+=x*(i-1);
            }
            cout << ans <<endl;
        }
    }
    else{
        if(a%2==0||b%2==0){
            long double ans=0;
            ll cnt=1;
            for(int i=2;i<=11;i+=g){
                long double x=1;
                rep(j,i)x/=i;
                ans+=x*cnt;
                cnt++;
            }
            cout << ans <<endl;
        }
        else{
            long double ans=0;
            ll cnt=1;
            for(int i=2;i<=15;i+=2*g){
                long double x=1;
                rep(j,i)x/=i;
                ans+=x*cnt;
                cnt+=2;
            }
            cout << ans <<endl;
        }
    }
}