HDU 4752

#include<cstdio>
#include<cstring>
#include<cmath>
#include<iostream>
#include<algorithm>
using namespace std;
int n,a,b,c,l,r;
double sqr(double x){return x*x;}
double len(double x)
{
    double t,tt;
    t=(sqrt((b+2*a*x)*(b+2*a*x)+1)+2*a*x+b);
    tt=log(t)/(4*a);
    t=sqrt((b+2*a*x)*(b+2*a*x)+1)*(b+2*a*x)/(4*a);
    tt+=t;
    return tt;
}
int x[20009],y[20009];
int main()
{
    int i;
    while(scanf("%d%d%d%d%d%d",&n,&a,&b,&c,&l,&r)!=EOF)
    {
        for(i=0;i<n;i++)
            scanf("%d%d",&x[i],&y[i]);
        x[n]=x[0],y[n]=y[0];
        double ans=0;
        for(i=0;i<n;i++)if(x[i]!=x[i+1])
        {
            double x0=x[i],y0=y[i];
            double x1=x[i+1],y1=y[i+1];
            if(x0>x1)swap(x0,x1),swap(y0,y1);
            double k=(y1-y0)/(x1-x0);
            double d=y1-k*x1;
            double u=sqr(b-k)-4*a*(c-d);
            double length=0;
            if(u>=0)
            {
                double t1=(-(b-k)*1.0+sqrt(u))/(2.0*a);
                double t2=(-(b-k)*1.0-sqrt(u))/(2.0*a);
                if(t1>t2)swap(t1,t2);
                t1=max(x0,max(t1,l*1.0));
                t2=min(x1,min(t2,r*1.0));
                if(t1<=t2)
                    length=fabs(len(t2)-len(t1));
                if(x[i]<x[i+1])ans+=length;
                else ans-=length;
            }
        }
        printf("%.2lf\n",fabs(ans));
    }
    return 0;
}