#include <iostream>
#include <fstream>
#include <deque>
#include <iomanip>
#define N 30005
using namespace std;
ifstream f("secv3.in");
ofstream g("secv3.out");
double timp[N],cost[N],rez,now;
int n,l,u;

double curent(int i)
{
    return((cost[i]-cost[i-l])/(timp[i]-timp[i-l]));
}

void citire()
{
    for(int i=1;i<=n;++i)
    {
        f>>cost[i];
        cost[i]+=cost[i-1];
    }
    for(int i=1;i<=n;++i)
    {
        f>>timp[i];
        timp[i]+=timp[i-1];
    }
}

int main()
{
    f>>n>>l>>u;
    citire();
    for(int i=l;i<=n;++i)
    {
        rez=max(rez,curent(i));
    }
    g<<setprecision(2)<<fixed<<rez;
    return 0;
}