#include<stdio.h>
int l,u,n,c[30010],t[30010];
float rmax=0;
void din(int ind)
{
   int i,s,e;
   unsigned long tc=0,tt=0;
   s=ind-u+1;
   if(s<1)s=1;
   e=ind-l+1;
   for(i=e;i>=s;i--)
   {
   	tc+=c[i];
      tt+=t[i];
      if(rmax<((float)tc/tt))
      	rmax=((float)tc/tt);
   }
}
int main()
{
	FILE *fi,*fo;
   fi=fopen("secv3.in","r");
   fo=fopen("secv3.out","w");
   fscanf(fi,"%d %d %d",&n,&l,&u);
   int i;
   for(i=1;i<=n;i++)
   	fscanf(fi,"%d",&c[i]);
   for(i=1;i<=n;i++)
   	fscanf(fi,"%d",&t[i]);
   for(i=l;i<=n;i++)
   	din(i);
   fprintf(fo,"%f",rmax);
   return 0;
}