using namespace std;

#include <set>
#include <map>
#include <list>
#include <deque>
#include <stack>
#include <queue>
#include <cmath>
#include <cctype>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <utility>
#include <iomanip>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>

#define pb push_back
#define size(V) ((int)(V.size()))
#define f first
#define s second
#define II inline
#define ll long long
#define db double
#define FORit(it, x) for (__typeof((x).begin()) it = (x).begin(); it != (x).end(); ++it)
#define REP(i, N) for (int i = 0; i < (int)(N); ++i)
#define FOR(i,a,b) for(int i=a;i<=b;++i)
#define all(v) v.begin() , v.end()
#define CC(v) memset((v),0,sizeof((v)))
#define CP(v,w) memcpy((v),(w),sizeof((w)))
#define mp make_pair
#define oo 1<<30

#define IN "secv3.in"
#define OUT "secv3.out"
#define N_MAX 1<<15

typedef vector<int> VI;
typedef pair<int,int> pi;
typedef vector<string> VS;
template<class T> string toString(T n) {ostringstream ost;ost<<n;ost.flush();return ost.str();}
typedef vector<string> VS;

int N,A,B,V[N_MAX],R[N_MAX];
double S[N_MAX];
deque<int> Q;

II void scan()
{
	freopen(IN,"r",stdin);
	freopen(OUT,"w",stdout);
	scanf("%d%d%d",&N,&A,&B);
	
	FOR(i,1,N) scanf("%d",V+i);
	FOR(i,1,N) scanf("%d",R+i);
}

II bool compute(double m)
{
	FOR(i,1,N) S[i] = S[i-1] + (double)V[i] - m * (double)R[i];
	Q.clear();
	
	double rez(-1),sum(0);
	
	FOR(i,1,N)
	{
		if(i < A)
			continue;
		sum = S[i] - S[i-A];
		
		for(;!Q.empty() && i - Q.front() > B;Q.pop_front() );
		for(;!Q.empty() && S[i] - S[ Q.back() ] <= sum;Q.pop_back() );
		
		Q.pb(i-A);
		rez = max(rez,S[i] - S[ Q.front() ]);
		if(rez > 0)
			return true;
	}
	return false;
}

II void solve()
{
	double a = 0,b = 1000;
	
	for(;a + 1E-2 < b;)
	{
		double m = (a + b) / 2;
		
		if(!compute(m) )
			b = m - 1E-3;
		else
			a = m;
	}
	
	printf("%.2lf\n",a);
}
	
int main()
{
	scan();
	solve();
	return 0;
}