#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("secv3.in");
ofstream g("secv3.out");
int main()
{
    int n, l, u, i, a[1000], b[1000], intermediar, val=0, s1, s2;
    double maxim=0;
    f>>n>>l>>u;
    for (i=1; i<=n; i++)
        f>>a[i];
    for (i=1; i<=n; i++)
        f>>b[i];
    intermediar=l;
    for (i=1; i<=n; i++) {
            if (a[i] == 0) break;
        s1+=a[i]; s2+=b[i]; ++val;
        if (val == intermediar) {
            if ((double)s1/s2 > maxim) maxim = (double)s1/s2;
            s1 = 0;
            s2 = 0;
            val = 0;
            i = i - intermediar +2;
        }
    }
    g<<fixed<<setprecision (2)<<maxim;
    return 0;
}