#include<fstream.h>
int a[30000],N,U,L;
void citire(){
ifstream fin("secv3.in");
fin>>N>>L>>U;
double x;
for (int i=0;i<N;i++)
  fin>>a[i];
for (int j=0;j<N;j++){
    fin>>x;
    a[j]=a[j]/x;}
fin.close();
}
double cost (int y,int n){
double S1=0;
     for (int i=y;i<n;i++)
	  S1+=a[i];
return S1;
}
double maxim (){
double max=0,S;
   for (int i=0;i<N-L+1;i++){
      S=cost(i,i+L);
      if (S>max)
      max=S;
      for (int j=i+L+1;j<=i+U;j++){
	 S+=a[j];
      if (S>max)
	   max=S;       } }
return max*100;
}
int main(){
citire();
ofstream fout("secv3.out");
long n=maxim();
fout<<n/100<<"."<<n%100;
fout<<"\n";
fout.close();
return 0;
}