#include <iostream>
#include <fstream>

using namespace std;

void sumasubset(){

	int a, b, n;
	float max = 0;

	ifstream in;
	in.open("secv3.in");
	ofstream out;
	out.open("secv3.out");

	in >> n >> a >> b;
	float *v,*time,*cost,*t,*c;

	time = (float *)malloc(n*sizeof(float));
	t = (float *)malloc(n*sizeof(float));
	cost = (float *)malloc(n*sizeof(float));
	c = (float *)malloc(n*sizeof(float));

	for (int i = 0; i < n; i++)
	{
		c[i] = 0;
		in >> cost[i];
	}
	for (int i = 0; i < n; i++)
	{
		t[i] = 0;
		in >> time[i];
	}
	for (int i = 0; i < b; i++)
	{
		for (int j = i; j < n; j++)
		{
			t[j] += time[j-i];
			c[j] += cost[j-i];
			if(c[j]/t[j] > max && i>=a-1){
				max = c[j]/t[j];
				//cout << max <<'\n';
			}
		}
	}

	out << max;

	in.close();
	out.close();

}

int main(){

	sumasubset();

}