#include<bits/stdc++.h>
using namespace std;

const int X = 30001;
double c[X], t[X];

int main() {
    freopen("secv3.in","r",stdin);
    freopen("secv3.out","w",stdout);
    int n, l, u, nr, m;
    double rez, a, b;

    scanf("%d %d %d", &n, &l, &u);

    for (int i = 1; i <= n; i++) {
        scanf("%d", &nr);
        c[i] = c[i - 1] + nr; }

    for (int i = 1; i <= n; i++) {
        scanf("%d", &nr);
        t[i] = t[i - 1] + nr; }

    rez = c[l] / t[l];
    m = 1;

    for (int i = l + 1; i <= n; i++) {
        if (i - l == u)
            m++;

        a = (c[i] - c[m - 1]) / (t[i] - t[m - 1]);
        b = (c[i] - c[i - l]) / (t[i] - t[i - l]);

        if (a < b) {
            a = b;
            m = i - l + 1; }

        rez = max(rez, a); }

    printf("%.2lf", rez);

    return 0; }