#include <bits/stdc++.h>
using namespace std;

ifstream fin("secv3.in");
ofstream fout("secv3.out");

const int NMAX=3e4+1;
int n, l, u, nr, st=1;
double c[NMAX], t[NMAX], med,  rez;

int main(){
    fin>>n>>l>>u;
    for(int i=1;i<=n;i++){
        fin>>c[i];
        c[i]+=c[i-1];
    }
    for(int i=1;i<=n;i++){
        fin>>t[i];
        t[i]+=t[i-1];
    }

    for(int i=l;i<=n;i++){
        if(st==i-u)
            st++;
        if((c[i]-c[st-1])/(t[i]-t[st-1])<=(c[i]-c[i-l])/(t[i]-t[i-l]))
            st=i-l+1;

        rez=max(rez, (c[i]-c[st-1])/(t[i]-t[st-1]));
        //cout<<i<<' '<<(c[i]-c[st-1])/(t[i]-t[st-1])<<endl;
    }
    fout<<fixed<<setprecision(2)<<rez;


    return 0;
}