#include <fstream>
#include <iomanip>
#define NMAX 30000

using namespace std;

ifstream cin("secv3.in");
ofstream cout("secv3.out");

int c[NMAX+1], t[NMAX+1];

int main()
{
    int n, l, u, val, lst=0;
    double ans;

    cin >> n >> l >> u;

    for(int i = 1; i <= n; i++){
        cin >> val;
        c[i] = c[i - 1] + val;
    }
    for(int i = 1; i <= n; i++){
        cin >> val;
        t[i] = t[i - 1] + val;
    }
    for(int i = 1; i <= n; i++){
        if(lst + u < i)
            lst++;
        if(i >= l){
            if(1. * (c[i] - c[lst]) / (t[i] - t[lst]) <= 1. * (c[i] - c[i - l]) / (t[i] - t[i - l]))
                lst = i - l;
            ans = max(ans, 1. * (c[i] - c[lst]) / (t[i] - t[lst]));
        }
    }
    cout << fixed << setprecision(2) << ans;
    return 0;
}