/*
100p
*/
#include<stdio.h>

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

void citire()
{
  long i;
  freopen("secv3.in","r",stdin);
  scanf("%ld%ld%ld",&n,&l,&r);
  for (i=1; i<=n; i++)
    scanf("%ld",c+i);
  for (i=1; i<=n; i++)
    scanf("%ld",t+i);
}


void calcul()
{

  long i, st, sc;
  for (u=l; u<=l+90 && 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++;
  }
  }

  freopen("secv3.out","w",stdout);
  printf("%.2f",maxim);
}


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