#include <fstream>
#include <deque>
using namespace std;

#define NMax 30005

ifstream f("secv3.in");
ofstream g("secv3.out");

int n,l,u;
int c[NMax],t[NMax];
double sum[NMax],minim[NMax];

int solve(double x)
{
    int i;
    deque<int> dq;

    for(i=1;i<=n;++i) sum[i]=sum[i-1]+c[i]-x*t[i];

    for(i=1;i<=n;i++)
    {
        if(i>=l) if(sum[i]-minim[i-l]>=0) return 0;

        while(!dq.empty() && sum[dq.back()]>sum[i]) dq.pop_back();
        dq.push_back(i);

        if(dq.front()<=i-u+l-1) dq.pop_front();

        minim[i] = sum[dq.front()];
    }

    return 1;
}

int main()
{
    int i;

    f>>n>>l>>u;
    for(i=1;i<=n;++i) f>>c[i];
    for(i=1;i<=n;++i) f>>t[i];

    int j=100000,step;
    double d;
    for(step=1;step<=j;step<<=1);
    for(;step;step>>=1)
    {
        d=(double)(j-step)/100;
        if( solve(d) ) j-=step;
    }

    g<<j/100<<"."<<j%100<<"\n";

    f.close();
    g.close();
    return 0;
}