#include<iostream>
#include<cstdio>
using namespace std;
const double s_h = 719./120,s_m = 59./10,m_h =11./120;
const double tsh=43200./719,tsm =3600./59,tmh =43200./11;
double MAX(double a,double b,double c)
{
    double max=a;
    if (b>max)
        max=b;
    if(c>max)
        max=c;
    return max;
}
double MIN(double a,double b,double c)
{
    double min=a;
    if (b<min)
        min=b;
    if (c<min)
        min=c;
    return min;
}
int main()
{

    double N;
    while (~scanf("%lf",&N))
    {
        if (N==-1)
            break;
        double bsm,bsh,bmh,esm,esh,emh,begin,end,sum=0;
        bsm=N/s_m;
        bsh=N/s_h;
        bmh=N/m_h;
        esm=(360-N)/s_m;
        esh=(360-N)/s_h;
        emh=(360-N)/m_h;
        for(double bt3=bsh,et3=esh;et3<=43200.000001;bt3+=tsh,et3+=tsh)
        {
            for (double bt2=bmh,et2=emh;et2<=43200.000001;bt2+=tmh,et2+=tmh)
            {
                if (et2<bt3)
                    continue;
                if (bt2>et3)
                    break;
                for (double bt1=bsm,et1=esm;et1<43200.000001;bt1+=tsm,et1+=tsm)
                {
                    if (et1<bt2||et1<bt3)
                        continue;
                    if (bt1>et2||bt1>et3)
                        break;
                    begin=MAX(bt1,bt2,bt3);
                    end=MIN(et1,et2,et3);
                    sum+=(end-begin);
                }
            }
        }
        printf("%.3lf\n",sum/432);
    }
    return 0;
}