#include <fstream>
#include <iomanip>

using namespace std;

ifstream cin("secv3.in");
ofstream cout("secv3.out");

const int nmax=30005;

int n,l,u,idx,x;
double cost[nmax],timp[nmax];

int main()
{
    cin>>n>>l>>u;

    for(int i=1;i<=n;i++)
    {
        cin>>x;
        cost[i]=x+cost[i-1];
    }

    for(int j=1;j<=n;j++)
    {
        cin>>x;
        timp[j]=x+timp[j-1];
    }

    double ans=0;

    for(int i=1;i<=n;i++)
    {
        if(idx+u<i)idx++;
        if(i>=l)
        {
            if((cost[i]-cost[i-l])/(timp[i]-timp[i-l])>=(cost[i]-cost[idx])/(timp[i]-timp[idx]))
                idx=i-l;
            ans=max(ans,(cost[i]-cost[idx])/(timp[i]-timp[idx]));
        }
    }

    cout<<fixed<<setprecision(2)<<ans;

    return 0;
}