#include <stdio.h>
#include <stdlib.h>
int x[100001],y[100001];
int deq[100001];
int main()
{
    int n,l,u,i,p,a,b;
    double max;
    freopen("secv3.in","r",stdin);
    freopen("secv3.out","w",stdout);
    scanf("%d%d%d",&n,&l,&u);
    for(i=1; i<=n; i++)
        scanf("%d",&x[i]);
    for(i=1; i<=n; i++)
        scanf("%d",&y[i]);
    /*for(i=1; i<=n; i++)
        printf("%d ",x[i]);
    printf("\n");
    for(i=1; i<=n; i++)
        printf("%d ",y[i]);
    printf("\n");*/
    for(i=1; i<=n; i++)
        x[i]=x[i-1]+x[i];
    for(i=1; i<=n; i++)
        y[i]=y[i-1]+y[i];
    max=(double)x[l]/y[l];
    deq[a=b=1]=1;
    for(i=l+1; i<=n; i++)
    {
        while(a<=b && deq[a]<=i-u)
            a++;
        while(b>=a && (double)x[deq[b]-1]/y[deq[b]-1]<(double)x[i-l]/y[i-l])
            b--;
        deq[++b]=i-l+1;
        if(max<(double)(x[i]-x[deq[a]-1])/(y[i]-y[deq[a]-1]))
            max=(double)(x[i]-x[deq[a]-1])/(y[i]-y[deq[a]-1]);
    }
    printf("%.2lf\n",max);


    return 0;
}