#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<math.h>
#define maxn 15
using namespace std;
const double eps=1e-7;
int n;
double l,r;
double a[maxn];
double myabs(double now)
{
	return now>0 ? now : -now;
}
double judge(double now)
{
	double ans=0.0;
	for(int i=0;i⇐n;i++)
	{
		ans+=a[i]*pow(now,i);
	} 
	return ans;
} 
int main()
{
	scanf(“%d%lf%lf”,&n,&l,&r);
	for(int i=n;i>=0;i–)
	scanf(“%lf”,&a[i]); 
	while(myabs(r-l)>=eps)
	{
		double mid1=l+((r-l)/3.0);
		double mid2=l+((r-l)/3.0*2.0);
		if(judge(mid1)>judge(mid2))
		{
			r=mid2;
		}
		else
		l=mid1;
	}
	printf(“%.5lf\n”,l);
}