#include <iostream>
#include <iomanip>
#include <fstream>
#define DN 30005
using namespace std;

int n,l,u,st,dr;
double v[DN],s[DN],t[DN];

bool check(double r) {
    st=1;dr=l;
    for(int i=1; i<=n; ++i) v[i]=v[i-1]+s[i]-r*t[i];
    if(v[u]>=0) return 1;
    for(int i=u+1; i<=n; ++i) {
        for(;i-st+1>u;++st);
        for(;i-st+1>l || v[i]-v[st]<0; ++st);
        if(v[i]-v[st-1]>=0) return 1;
    }
    return 0;
}

int main()
{
    ifstream f("secv3.in");
    ofstream g("secv3.out");
    f>>n>>l>>u;
    for(int i=1; i<=n; ++i) f>>s[i];
    for(int i=1; i<=n; ++i) f>>t[i];
    double ls=0,ld=99999999,m;

    for(int i=1; i<=1000; ++i) {
        m=(ls+ld)*0.5;
        if(check(m)) ls=m;
        else ld=m;
    }
    g<<fixed<<setprecision(2)<<ls;
    return 0;
}