#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;

vector<int> prime_dice={2,3,5,7,11,13};
vector<int> comp_dice={4,6,8,9,10,12};

ll calc(int P,int C,ll pro){
    if(P==0&&C==0){
        return pro;
    }
    ll ret=0;
    if(P==0){
        for(int i:comp_dice){
            ret+=calc(P,C-1,pro*i);
        }
    }
    else{
        for(int i:prime_dice){
            ret+=calc(P-1,C,pro*i);
        }
    }
    return ret;
}

int main(){
    int P,C;
    cin>>P>>C;
    cout<<fixed<<setprecision(20);
    cout<<calc(P,C,1)/pow(6,P+C)<<endl;
}