#include <iostream>
#include <fstream>
#include <iomanip>

using namespace std;
ifstream fin("secv3.in");
ofstream fout("secv3.out");
int n,l,u,i,j,sf;
double maxi,a[30002],c[30002],p[30002],t[30002];
int main()
{
    fin>>n>>u>>l;
    for(i=1;i<=n;++i)
    {
        fin>>c[i];
        p[i]=p[i-1]+c[i];
    }
    for(i=1;i<=n;++i)
    {
        fin>>a[i];
        t[i]=t[i-1]+a[i];
    }
    for(i=1;i<=n-u+1;++i)
    {
        for(j=i+u-1,sf=min(n,i+min(l-1,u+1000));j<=sf;++j)
        {
            if(p[j]-p[i-1]>maxi*(t[j]-t[i-1]))
            {
                maxi=(p[j]-p[i-1])/(t[j]-t[i-1]);
            }
        }
    }
    fout<<fixed<<setprecision(2)<<maxi<<'\n';

    return 0;
}