#include <bits/stdc++.h>
std::ifstream fin("secv3.in");
std::ofstream fout("secv3.out");
int n, l, u;
double left, right, mid, sum, max;
std::pair<double, double> list[30005];
double numbers[30005];
bool check(double val);
int main()
{
    fin>>n>>l>>u;
    for(int i=1; i<=n; ++i) fin>>list[i].first;
    for(int i=1; i<=n; ++i) fin>>list[i].second;
    left=0.0, right=1000.0;
    for(int k=1; k<=100; ++k){
        mid=(left+right)/2;
        if(check(mid)) left=mid;
        else right=mid;
    }
    fout<<std::fixed<<std::setprecision(2)<<left;
    return 0;
}
bool check(double val){
    for(int i=1; i<=n; ++i) numbers[i]=list[i].first-list[i].second*val;
    sum=0; max=DBL_MIN;
    for(int i=1; i<l; ++i){
        sum+=numbers[i];
    }
    for(int i=l; i<=n; ++i){
        sum+=numbers[i];
        sum-=numbers[i-l];
        if(sum>max) max=sum;
    }
    if(sum>=0) return true;
    else return false;
}