#include <bits/stdc++.h>

using namespace std;
ifstream in("secv3.in");
ofstream out("secv3.out");
int n, l, u;
long double cost[30005], timp[30005], sus, jos, ans;
int main()
{
    in>>n>>l>>u;
    for (int i = 1; i <= n; i++)
        in>>cost[i];

    for (int i = 1; i <= n; i++)
        in>>timp[i];

    for (int i = 1; i <= n; i++) {
        sus = 0;
        jos = 0;
        for (int j = i; j >= max(1, j - u + 1); j--) {
            sus += cost[j];
            jos += timp[j];
            if (j - i + 1 >= l)
                if (fabs(sus / jos - ans) > 0.01) ans = sus / jos;
        }
    }

    out<<fixed<<setprecision(2)<<ans;

}