HDU1006

#include <stdio.h>
#include <math.h>
#include<iostream>
#include <algorithm>
using namespace std;
struct qujian
{
    double l,r;
};
double D;

qujian solve(double a,double b)   //解方程 D<=a*x+b<=360-D ,并且和 [0,60] 取交集
{
    qujian p1;
    if(a>0)
    {
        p1.l=(D-b)/a;
        p1.r=(360-D-b)/a;
    }
    else
    {
        p1.l=(360-D-b)/a;
        p1.r=(D-b)/a;
    }
    if(p1.l<0)
        p1.l=0;
    if(p1.r>60)
        p1.r=60;
    if(p1.l>=p1.r)
        p1.l=p1.r=0;
    return p1;
}
qujian compare(qujian a,qujian b)
{
    qujian p;
    p.l=max(a.l,b.l);
    p.r=min(a.r,b.r);
    if(p.l>p.r)
        p.l=p.r=0;
    return p;
}




double happytime(double h,double m)
{
    double a,b;
    int i,j,k;
    qujian s[3][2],p2;      //解方程D<=|hh-mm|<=360-D
    a=1.0/120.0-0.1;        //hh=30*h+m/2+s/120;
    b=30*h+m/2.0-6*m;
    s[0][0]=solve(a,b);
    s[0][1]=solve(-a,-b);

    a=0.1-6;
    b=6*m;
    s[1][0]=solve(a,b);
    s[1][1]=solve(-a,-b);

    a=1.0/120-6;
    b=30*h+m/2.0;
    s[2][0]=solve(a,b);
    s[2][1]=solve(-a,-b);

    double ans=0;
    for(i=0; i<2; i++)
    {
        for(j=0; j<2; j++)
            for(k=0; k<2; k++)
            {
                p2=compare(compare(s[0][i],s[1][j]),s[2][k]);
                ans+=p2.r-p2.l;
            }
    }
    return ans;
}

int main()
{
    while(scanf("%lf",&D))
    {
        if(D==-1)
            break;
        double h,m,ans=0;
        for(h=0; h<12; h++)
        {
            for(m=0; m<60; m++)
                ans+=happytime(h,m);
        }
        printf("%.3lf\n",ans*100.0/(60*60*12));
    }
    return 0;
}