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

#define NMax 30005
#define inf 2100000000

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

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

int solve(int x)
{
    int i,mx=-inf;
    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(mx<sum[i]-minim[i-l]) mx=sum[i]-minim[i-l];

        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()];
    }

    if(mx>=0) return 0;
    return 1;
}

int main()
{
    int i;

    f>>n>>l>>u;
    for(i=1;i<=n;++i) f>>c[i],c[i]*=100;
    for(i=1;i<=n;++i) f>>t[i];

    int j=1000,step;
    for(step=1;step<=j;step<<=1);
    for(;step;step>>=1) if( solve(j-step) ) j-=step;

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

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