#include <fstream>

using namespace std;
ifstream fin("secv3.in");
ofstream fout("secv3.out");
int cost[30010],timp[30010],T,t,C,c,i,j,Maxi,n,l,u;
double Max;

int main()
{
    fin>>n>>l>>u;
    for (i=1;i<=n;i++)
        fin>>cost[i];
    for (i=1;i<=n;i++)
        fin>>timp[i];
    for (i=1;i<=l;i++)
    {
        C+=cost[i];
        T+=timp[i];
    }
    Max=(double)C/T;
    for (i=1;i<=n-l+1;i++)
    {
        c=C;
        t=T;
        for (j=i+l;j<=i+u-1;j++)
        {
            c+=cost[j];
            t+=timp[j];
            if ((double)c/t>Max)
                Max=(double)c/t;
        }
        C-=cost[i];
        C+=cost[i+l];
        T-=timp[i];
        T+=timp[i+l];
    }
    Maxi=(int)100*Max;
    Max=(double)Maxi/100;
    fout<<Max;
    return 0;
}