#include <cstdio>
#include <vector>
#include <queue>
#include <stack>
#include <list>
#include <set>
#include <algorithm>
#include <utility>
#include <string>
#include <functional>
#include <sstream>
#include <fstream>
#include <iostream>
using namespace std;
#define FOR(i,a,b) for (i=a;i<=b;i++)
#define fori(it,v) for (it=(v).begin();it!=(v).end();it++)
#define pb push_back
#define mp make_pair
#define fs first
#define ss second
#define all(c) c.begin(),c.end()
#define pf push_front
#define popb pop_back
#define popf pop_front
long long n,L,u,a[30005],b[30005],s[30005];
int ver(long long y)
{
	bool rez=0;
	int i;
	deque<int> q;
	FOR(i,1,n)
	{
		s[i]=s[i-1]+a[i]-y*b[i];
		if (i<L)
			continue ;
		long long sum=s[i]-s[i-L];
		while (!q.empty()&&i-q.front()>u)
			q.popf();
		while (!q.empty()&&s[i]-s[q.back()]<=sum)
			q.popb();
		q.pb(i-L);
		rez|=(s[i]-s[q.front()]>=0);
	}
	return rez;
}
int main()
{
	FILE *in,*out;
	in=fopen("secv3.in","r");
	out=fopen("secv3.out","w");
	long long i;
	fscanf(in,"%lld%lld%lld",&n,&L,&u);
	FOR(i,1,n)
	{
		fscanf(in,"%lld",&a[i]);
		a[i]*=1000;
	}
	FOR(i,1,n)
		fscanf(in,"%lld",&b[i]);
		
	long long rez=0;
	for (i=1<<20;i;i>>=1)
	{
		rez+=i;
		if (ver(rez))
			rez-=i;
	}
	rez++;
	fprintf(out,"%lld.%lld\n",rez/1000,rez%1000);
	fclose(in);
	fclose(out);
	return 0;
}