#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;

const double h_m=11.0/120,h_s=719.0/120,m_s=59.0/10;    //相对角速度
const double Th_m=43200.0/11,Th_s=43200.0/719,Tm_s=3600.0/59;  //周期

int main()
{
    double d;
    while(scanf("%lf",&d)!=EOF&&d>=0)
    {
        ///d/h_m
        double sh_m=d/h_m;
        double eh_m=(360.0-d)/h_m;
        double sh_s=d/h_s;
        double eh_s=(360.0-d)/h_s;
        double sm_s=d/m_s;
        double em_s=(360.0-d)/m_s;
        double s1,e1,s2,e2,s3,e3,s4,e4,res=0;
        for(s1=sh_m,e1=eh_m;e1<=43200.000001;s1+=Th_m,e1+=Th_m)
        {
            for(s2=sh_s,e2=eh_s;e2<=43200.000001;s2+=Th_s,e2+=Th_s)
            {
                if(e1<=s2)
                    break;
                if(e2<=s1)
                    continue;
                for(s3=sm_s,e3=em_s;e3<=43200.000001;s3+=Tm_s,e3+=Tm_s)
                {
                    if(s3>=e2||s3>=e1)
                        break;
                    if(e3<=s2||e3<=s1)
                        continue;
                    s4=max(s1,max(s2,s3));
                    e4=min(e1,min(e2,e3));
                    res+=(e4-s4);
                }
            }
        }
        printf("%.3lf\n",res/432);
    }
    return 0;
}