#include<queue>
#include<stdio.h>
using namespace std;
#define DIM 30010
int n,l,u;
int c[DIM],t[DIM];
double calc()
{
	deque <int> dq;
	dq.push_back(0);
	double Max=-(1<<30);
	for(int i=l;i<=n;i++)
	{
		if((double)(c[i]-c[dq.back()])/(t[i]-t[dq.back()])>Max)
			Max=(double)(c[i]-c[dq.back()])/(t[i]-t[dq.back()]);
		if((double)(c[i]-c[dq.front()])/(t[i]-t[dq.front()])>Max)
			Max=(double)(c[i]-c[dq.front()])/(t[i]-t[dq.front()]);
		while(!dq.empty()&&(double)c[dq.back()]/t[dq.back()]<=(double)c[i-l+1]/t[i-l+1])
			dq.pop_back();
		dq.push_back(i-l+1);
		if(dq.front()==i-u)
			dq.pop_front();
	}
	return Max;
}
int main()
{
	freopen("secv3.in","r",stdin);
	freopen("secv3.out","w",stdout);
	scanf("%d%d%d",&n,&l,&u);
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&c[i]);
		c[i]+=c[i-1];
	}
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&t[i]);
		t[i]+=t[i-1];
	}
	printf("%.2lf\n",calc());
	return 0;
}