#include <bits/stdc++.h>
using namespace std;const int MAXN=3e4+5;int n,l,u,i,c[MAXN],t[MAXN];deque<int>q;int main(){freopen("secv3.in","r",stdin);freopen("secv3.out","w",stdout);cin>>n>>l>>u;for(i=1;i<=n;i++)cin>>c[i],c[i]+=c[i-1];for(i=1;i<=n;i++)cin>>t[i],t[i]+=t[i-1];double ans=1.0*c[l]/t[l];for(i=l;i<=n;i++){while(q.size()&&q.front()<=i-u)q.pop_front();while(q.size()&&1LL*(c[i]-c[q.back()-1])*(t[i]-t[i-l])<1LL*(c[i]-c[i-l])*(t[i]-t[q.back()-1]))q.pop_back();q.push_back(i-l+1);ans=max(ans,1.0*(c[i]-c[q.front()-1])/(t[i]-t[q.front()-1]));}printf("%.2lf",ans);return 0;}