#include <bits/stdc++.h>

using namespace std;

int dx[]={2,3,5,7,11,13};
int dy[]={4,6,8,9,10,12};

int main(){
        int K;
        vector<long>data;
        data.resize(200);
        for(auto x:dx){
                for(auto y:dy){
                        data[x*y]++;
                }
        }

        cin>>K;
        switch(data[K]){
                case 0:cout<<fixed<<setprecision(13)<<0.00000000000000000<<endl;break;
                case 1:cout<<fixed<<setprecision(13)<<0.0277777777777777778<<endl;break;
                case 2:cout<<fixed<<setprecision(13)<<0.0555555555555555556<<endl;break;
        }
}