#include<stdio.h>
#define maxn 30001
FILE*fin=fopen("secv3.in","r");
FILE*fout=fopen("secv3.out","w");
int main()
{
int n,u,i,j,n1,n2,l,tp[maxn],c[maxn],t[maxn],cost[maxn];
double max=-1;
tp[0]=0;cost[0]=0;
fscanf(fin,"%d%d%d",&n,&l,&u);
for(i=1;i<=n;i++)
{
	fscanf(fin,"%d",&c[i]);
	cost[i]=cost[i-1]+c[i];
}
for(i=1;i<=n;i++)
{
	fscanf(fin,"%d",&t[i]);
	tp[i]=tp[i-1]+t[i];
}
for(i=l;i<=n;i++)
{
	for(j=i-u+1;j<=i-l+1;j++)
	{
		n1=cost[i]-cost[j-1];
		n2=tp[i]-tp[j-1];
		double r=(double)n1/(double)n2;
		if(r>max) max=r;
	}
}
fprintf(fout,"%.2lf",max);
fclose(fin);
fclose(fout);
return 0;
}