#include<cstdio>
using namespace std;
FILE *f,*g;
int a,b,i,x,j,n,u,l,s2[30001];
float c,maxi,s1[30001];
int main()
{f=fopen("secv3.in","r");
g=fopen("secv3.out","w");
fscanf(f,"%d%d%d",&n,&l,&u);
for(i=1;i<=n;++i)
	fscanf(f,"%d",&a),s1[i]=s1[i-1]+a;
for(i=1;i<=n;++i)
	fscanf(f,"%d",&b),s2[i]=s2[i-1]+b;
for(i=l;i<=n;++i)
{c=(s1[i]-s1[i-l])/(s2[i]-s2[i-l]);
if(maxi<c)
	maxi=c;
x=i+u-l;
if(x>n)
	x=n;
for(j=1;j<=x;++j)
{c=(s1[j]-s1[i-l])/(s2[j]-s2[i-l]);
if(c>maxi)
	maxi=c;
}}
fprintf(g,"%.2f",maxi);
fclose(f);
fclose(g);
return 0;
}