#include<stdio.h>

 FILE *f=fopen("secv3.in","r");
 FILE *g=fopen("secv3.out","w");
 int a,b,x[3000],y[3000],n,i,j,l;
 float c[3000],max,s,s1;

int main()
{
 fscanf(f,"%d",&n);
 fscanf(f,"%d",&a);
 fscanf(f,"%d",&b);
 max=0;
 a--;
 b--;
 for(i=1;i<=n;i++)
    fscanf(f,"%d",&x[i]);
  for(i=1;i<=n;i++)
    fscanf(f,"%d",&y[i]);
   for(i=1;i<=n-a;i++)
 {
  for(j=a;j<=b;j++)
  {s=0;
  s1=0;
   for(l=i;l<=i+j;l++)
   { s=s+x[i];
     s1=s1+y[i];
   }
   if((float)s/s1>max)
    max=(float)s/s1;
  }

 }
 fprintf(g,"%3.2f",max);
 fcloseall();
 return 0;
}