#include<fstream.h>
#include<stdio.h>

long c[30000], t[30000], n, l, u, r;
float maxim;

void citire()
{
  long i;
  ifstream in("secv3.in");
  in>>n;
  in>>l;
  in>>r;
  for (i=1; i<=n; i++)
    in>>c[i];
  for (i=1; i<=n; i++)
    in>>t[i];
}


void calcul()
{

  long i, st, sc;
  for (u=l; u<r; u++)
  {
  st=sc=0;
  for (i=1; i<=u; i++){ sc+=c[i]; st+=t[i];}
  if ((float)sc/st>maxim) maxim=(float)sc/st;
  while (i<=n)
  {
    sc-=c[i-u];
    st-=t[i-u];
    sc+=c[i];
    st+=t[i];
    if ((float)sc/st>maxim) maxim=(float)sc/st;
    i++;
  }
  }

  FILE *out=fopen("secv3.out","w");
  fprintf(out,"%.2f",maxim);
  fclose(out);
}


int main()
{
  citire();
  calcul();
  return 0;
}