#include <fstream>
#include <iomanip>
#define LE 30006
using namespace std;
ifstream f("secv3.in");
ofstream g("secv3.out");
int n,L,U,LI,i;
float TB,CB,C[LE],T[LE],cost,timp,MAX;
void citire ()
{
     f>>n>>L>>U;
     for(i=1;i<=n;i++) 
     f>>C[i];
     for(i=1;i<=n;i++)
     f>>T[i];
}
int main()
{
    citire();
    for(i=1,LI=1;i<=n;i++)
    {
        cost+=C[i];
        timp+=T[i];
        if(i-LI+1>U)
        {
            cost-=C[LI],timp-=T[LI];
            TB-=C[LI],CB-=T[LI];
            LI=i-L;
        }
        if (i>L)
        {
            CB+=C[i-L];
            TB+=T[i-L];
            if ((cost-CB)/(timp-TB)>cost/timp)
            {
                cost-=CB,timp-=TB;
                LI=i-L+1;
                CB=0,TB=0;
            }
        }
        if(i>=L)
        MAX=max(MAX,cost/timp);
    }
    g<<fixed;
    g<<setprecision(3)<<MAX<<'\n';
    f.close();
    g.close();
    return 0;
}