#include <iostream>
#include <cmath>
using namespace std;
//#define double long double
const double eps=0.00001;
int n;
double l,r,m,lm,rm,a[14];
double f(int x){
	double ans=0;
	for(int i=n;i>=0;i--){
		ans+=a[i]*pow(x,i); 
	}
	return ans;
}
int main(void){
	cin>>n>>l>>r;
	for(int i=n;i>=0;i--){
		cin>>a[i];
	}
	while(r-l>=eps){
		m=(r+l)/2;
		lm=m-eps;
		rm=m+eps;
		if(f(rm)>f(lm)){
			l=lm;
		}else{
			r=rm;
		}
		//cout<<l<<" "<<r<<" "<<lm<<" "<<rm<<" "<<m<<endl;
	}
	cout<<r;
	//cout<<l<<" "<<r<<" "<<lm<<" "<<rm<<" "<<m<<endl;
}