#include<bits/stdc++.h>
using namespace std;
double n,s,e,ans,sum;
double q[100005];
int h=1,t=1;
int main(){
	cin>>n>>s>>e;
	for(int i=1;i<=n;i++) cin>>q[i];
	while(t-h<s){
		t++;
		sum+=q[t-1];
	}
	ans=max(ans,sum/(t-h));
	while(t<=n){
		t++;
		sum+=q[t-1];
		if(t-h>e){
			sum-=q[h];
			h++;
		}
		while(q[h]<q[t-1]&&t-h>s){
			sum-=q[h];
			h++;
		}
		ans=max(ans,sum/(t-h));
	}
	cout<<fixed<<setprecision(3)<<ans;
}