#include <iostream>
#include <fstream>
#include <iomanip>
#define castor 30005
using namespace std;
ifstream fin("secv3.in");
ofstream fout("secv3.out");
struct emilutz
{
    double c,t;
}v[castor];
int n,l,u,a,i,j=1;
double s,mxs,ss;
int main()
{
    fin>>n>>l>>u;
    for (i=1;i<=n;i++)
    {
        fin>>a;
        v[i].c=v[i-1].c+a;
    }
    for (i=1;i<=n;i++)
    {
        fin>>a;
        v[i].t=v[i-1].t+a;
    }
    mxs=v[l].c/v[l].t;
    for (i=l+1;i<=n;i++)
    {
        if (i-l==u)
            j++;
        s=(v[i].c-v[j].c)/(v[i].t-v[j].t);
        ss=(v[i].c-v[i-l].c)/(v[i].t-v[i-l].t);
        if (s<ss)
        {
            s=ss;
            j=i-l+1;
        }
        mxs=max(s,mxs);
    }
    fout<<fixed<<setprecision(2)<<mxs;
    return 0;
}