#include <stdio.h>
long s1[30001],s2[30001];
int c[30001],x[30001],a[30001];
long i,k,n,t=1,l;
long double max,q,p;
int main()
{
FILE *f=fopen("secv3.in","r"), *g=fopen("secv3.out","w");
fscanf(f,"%ld %ld %ld",&n,&k,&l);
for (i=1;i<=n;i++)
        {
                fscanf(f,"%d",&c[i]);
                s1[i]=s1[i-1]+c[i];
        }
for (i=1;i<=n;i++)
        {
                fscanf(f,"%d",&x[i]);
                s2[i]=s2[i-1]+x[i];
                a[i]=c[i]-x[i];
        }
max=s1[k];
max=max/s2[k];
for (i=1;i<=n-k;i++)
        {
                if (i-t+1>l-k) t++;
                q=(s1[i+k]-s1[t-1]);
                q=q/(s2[i+k]-s2[t-1]);
                p=(s1[i+k]-s1[i]);
                p=p/(s2[i+k]-s2[i]);
                if (p>q) {t=i+1;q=p;}
                if (max<q)
                        {
                        max=q;
                        }
        }
fprintf(g,"%.2Lf",max);
fclose(f);
fclose(g);
return 0;
}