#include <fstream>
#include <algorithm>
#include <iomanip>
#define x first
#define y second

using namespace std;

ifstream fin("secv3.in");
ofstream fout("secv3.out");

int n,i,mini,maxi,j,b,c,d;
double sum1,sum2,a,maxi1;
pair<int,int> v[30001];


int main()
{
    fin >> n >> mini >> maxi;

    for(i = 1; i <= n; ++i)
        fin >> v[i].x;

    for(i = 1; i <= n; ++i)
        fin >> v[i].y;

    for(i = 1; i <= n; ++i)
        {for(j = i+mini-1; j <= i + maxi-1; ++j)
            {
                sum1+=v[j].x;
                sum2+=v[j].y;
            }
        a = sum1/sum2;
        sum1 = 0;
        sum2 = 0;
        if(a>maxi1)
            maxi1 = a;}

    fout << setprecision(2)<<maxi1;


    return 0;
}