using namespace std;
#include<stdio.h>
#include<deque>
#define inf 0x3f3f3f3f
deque<int>Q;
#define nmax 30001
int x,n,l,u,i;
float maxim,v,c[nmax],t[nmax];

void read()
{
	freopen("secv3.in","r",stdin);
	scanf("%d%d%d",&n,&l,&u);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&x);
		c[i]=c[i-1]+x;
	}
	for(i=1;i<=n;i++)
	{
		scanf("%d",&x);
		t[i]=t[i-1]+x;
	}
}

int main()
{
	read();
	maxim=-inf;
	for(i=1;i<=n;i++)
	{	
		Q.push_back(i);
		while(Q.front()+u-1<i) Q.pop_front();
		if(Q.front()+l-1<=i)
			{
				v=(c[i]-c[Q.front()-1])/(t[i]-t[Q.front()-1]);
				if(v>maxim)
				maxim=v; 
			}	
	}
	while(!Q.empty())
	{
		v=(c[n]-c[Q.front()-1])/(t[n]-t[Q.front()-1]);
		if(v>maxim)
		maxim=v; 
		Q.pop_front();
	}
	freopen("secv3.out","w",stdout);
	printf("%5.2f",maxim);
	return 0;
}