#include<iostream>
#include<fstream>
#include<iomanip>
using namespace std;
ifstream fi("secv3.in");
ofstream fo("secv3.out");
int main()
{
	int n,u,l,a[30005],b[30005];
	float max=0,cost=0,s=0;
	fi>>n>>u>>l;
	for(int i=1;i<=n;i++)
		fi>>a[i];
	for(int i=1;i<=n;i++)
		fi>>b[i];
	for(int i=1;i<=n;i++)
	{s=0;cost=0;
		for(int j=i;j<=i+l;j++)
			{s+=a[j];
			 cost+=b[j];
			 if(j-i>=u)
				if(max<s/cost)
					max=s/cost;
			}
	}
	fo<<max;
}