#include<bits/stdc++.h>
using namespace std;


int main()
{
    int a,b,n;
    while(cin>>n&& n)
    {
        a=n%5;
        if(a==0)
            cout<<"0.00"<<endl;
        else if(a==4 || a==1)
            cout<<"0.40"<<endl;
        else
            cout<<"0.20"<<endl;
    }
    return 0;
}