#include<stdio.h>
FILE *f=fopen("secv3.in","r"),
     *g=fopen("secv3.out","w");
int n,c[30003],i,j,k,x=1,y=10000,l,u,m,t[30003],sc,st;
float a,b;
int main()
{ fscanf(f,"%d %d %d",&n,&l,&u);
  for(i=1;i<=n;++i) fscanf(f,"%d",&t[i]);
  for(i=1;i<=n;++i) fscanf(f,"%d",&c[i]);
  --l;--u;
  m=n-l;
  for(i=1;i<=m;++i) { k=i+u;sc=0;st=0;
		      if(k>n) k=n;
		      for(j=i;j<=n;++j) { sc+=c[j];
					  st+=t[j];
					  if(st*y>sc*x) x=st,y=sc;
					}
		    }
  a=x;
  b=y;
  fprintf(g,"%.2f\n",a/b);
  fclose(f);
  fclose(g);
  return 0;
}