#include <stdio.h>
#define IN "secv3.in"
#define OUT "secv3.out"
#define L 30010

using namespace std;

int A[L], B[L];
int n, u, l;

double Rez=0;

void citire()
{
    scanf ("%d %d %d", &n, &u, &l);

    for (int i=0;i<n;i++)
        scanf ("%d ", &A[i]);

    for (int i=0;i<n;i++)
        scanf ("%d ", &B[i]);
}

void solve()
{
    double S1,S2;
    for (int i=max(l-100,u);i<=l;i++)
    {
        S1=S2=0;
        for (int j=0;j<i;j++)
        {
            S1+=A[j];
            S2+=B[j];
        }
        if (S1/S2>Rez)
            Rez=S1/S2;
        for (int j=i;j<n;j++)
        {
            S1+=A[j];
            S2+=B[j];
            S1-=A[j-i];
            S2-=B[j-i];
            if (S1/S2>Rez)
                Rez=S1/S2;
        }
    }

    printf("%.2lf",Rez);

}
int main ()
{
    freopen (IN ,"r", stdin);
    freopen (OUT ,"w", stdout);
    citire();
    solve();
    return 0;
}